After driving from Pakistan the previous day to a U.N. “encashment” center on the outskirts of Kabul, a family of Afghans wake up at dawn and boil tea after a night sleeping on top of the trucks that carried them. (Andrew Quilty for The Washington Post)

KABUL — Abdulhalim fled the northern city of Kunduz this month after militants and security forces had been clashing for days.

Now he’s 200 miles away in Kabul, sleeping in a tent and living on aid. He is part of a looming humanitarian crisis aid agencies here are struggling to contain.

Before the current crisis, more than a million people had already been uprooted last year. This year, at least another million Afghans are “on the move” inside Afghanistan and across its borders, in what the United Nations warns is an alarming new wave of displaced people.

Many, like Abdulhalim, fled violence or conflict; others escaped hardships such as poverty or drought. Still others were forced to return from Pakistan and Iran.

Even as the numbers grew, Afghanistan agreed to accept ­Afghan asylum seekers deported from the European Union. The deal, signed in October, could lead the E.U. to construct a separate terminal for deportees at Kabul’s international airport, and as many as 100,000 Afghans could return.

“This sudden increase [in the displaced] has put a lot of pressure on Afghanistan, which has had 30 years of war,” said Nader Farhad, spokesman for the U.N. refugee agency in Kabul. “It’s not easy to put together the infrastructure, to provide the services that are required,” he said, adding that the displaced need everything from food and blankets to jobs and health care.

“To the European countries, we say: Instead of investing in the return of Afghans to Afghanistan, tackle the root causes,” Farhad said. If the United Nations and other aid agencies fail to provide emergency assistance, “it will be a humanitarian crisis,” he said.

Families wait outside for a U.N. “encashment” center to open last month on the outskirts of Kabul. Afghan returnees are provided with health checks, immunizations, and needs assessments. (Andrew Quilty for The Washington Post)

Massive displacement has plagued Afghanistan for years, beginning with the Soviet invasion in 1979.

That conflict kindled two decades of war. When the United States invaded in 2001, some 4 million Afghans were living in Pakistan and Iran.

[Europe pressing harder on countries to take back deported migrants]

Many of those refugees later returned, driven by hopes for stability and peace. But now, ­Afghanistan is witnessing some of its worst violence since the United States helped to topple the Taliban.

More than 1,600 civilians were killed in the first six months of 2016, according to a U.N. report released in July. That was the highest number of civilian casualties in the first half of a year since the United Nations began keeping track in 2009.

The violence has been driven by Taliban assaults on Afghan cities, putting more civilians in the crosshairs. And the clashes have pushed even more people from their homes.

“The fighting was intense. There was artillery, rockets, aerial bombardment,” Abdulhalim, 38, said of this month’s days-long battle between Afghan and Taliban forces in Kunduz city. Insurgents briefly seized the city at the same time last year.

“My children were screaming, our neighbors’ houses destroyed,” said Abdulhalim, who like many Afghans goes by one name. “We had no option but to leave.”

Afghan children arrive outside the U.N. center on the outskirts of Kabul. (Andrew Quilty for The Washington Post)

A man prays beside the truck that carried him and his family to the center. (Andrew Quilty for The Washington Post)

In Helmand province, in the restive south, more than 60,000 people have been displaced this year, according to the United Nations, and militants have fought pitched battles in the provincial capital, Lashkar Gah.

At least 5,000 of those displaced in Helmand were forced out only in the past two months, the United Nations says, and thousands more have fled to neighboring provinces and beyond.

“In some provinces, the [armed] groups have more power there, and the government, it is very difficult for us to reach” the affected population, said Sayed Rohullah Hashemi, an adviser to the minister of refugees and repatriation. “We don’t have the capacity to do so, especially in our ministry. The government cannot reach everyone on its own.”

In a dusty lot east of Kabul, the U.N. refugee agency has erected a center for the hundreds of thousands of Afghan refugees arriving from Pakistan. At least 5,000 refugees cross the border from Pakistan every day. The United Nations gives them a small stipend and vaccinates the children against measles and polio.

[Afghan refugees, settled in Pakistan for decades, are being ordered to leave]

The influx began after Pakistani authorities announced a deadline for Afghan refugees — of which there were 1.7 million registered with the United Nations — to leave. Many of the refugees had lived in Pakistan for decades, or were even born there after their parents had fled Afghanistan.

Jumauddin, 27, was born in Pakistan to Afghan parents. Now he is heading to Kunduz province, to the Khanabad district, where Taliban fighters hold sway. He says he has no choice.

“Kabul is too expensive, and maybe in Kunduz I can plow a plot of land,” Jumauddin said. “I know that there was fighting there even last week, but I have no other option.”

More Afghan refugees arrive from Pakistan. (Andrew Quilty for The Washington Post)

The government is worried about the return of refugees to areas where insurgents are active. But right now, the Taliban controls more territory than at any time since 2001.

“We are facing the return of tens of thousands of Afghans each month. . . . This will add very much to the vicious cycle of insecurity and joblessness,” said Bashir Bezhen, an Afghan analyst and political commentator.

Reports have already surfaced of returning refugees clashing with locals over resources and land. The displaced are often rejected, or pushed into squalid camps. They also face the threat of forced eviction and rarely have access to clean water or food.

“They are the poorest of the poor. They often live in open air,” the U.N.’s Farhad said. “But they should go back [to their homes] when they feel secure. It has to be voluntary and of their own accord.”

In the area where Abdulhalim took shelter, the displaced worried that the government would force them out. The fighting in Kunduz city had subsided, but they couldn’t just pack up and go home.

“They want us gone from here, but we don’t have anything, not even the money to get back,” Abdulhalim said. He first fled Kunduz on foot, with his children and the clothes on his back.

Bezhen said that the government “is incapable of creating jobs for these people or of improving the economy in the remote places where they live.” He said criminal and terrorist networks will seek out the jobless and displaced youths.

“It will push Afghanistan into deeper crisis,” Bezhen said.

Senior FBI officials were informed about the discovery of new emails potentially relevant to the investigation of Hillary Clinton’s private email server at least two weeks before Director James B. Comey notified Congress, according to federal officials familiar with the investigation.

The officials said that Comey was told that there were new emails before he received a formal briefing last Thursday, although the precise timing is unclear.

The information goes beyond the details provided in the letter that Comey sent to lawmakers last week declaring that he was restarting the inquiry into whether Clinton mishandled classified material during her tenure as secretary of state. He wrote in the Friday letter that “the investigative team briefed me yesterday” about the additional emails.

The people familiar with the investigation said that senior officials had been informed weeks earlier that a computer belonging to former congressman Anthony Weiner (D-N.Y.) contained emails potentially pertinent to the Clinton investigation. Clinton’s top aide, Huma Abedin, was married to Weiner; the two are now separated.

Comey did not notify Congress as soon as he learned about the emails because officials wanted additional information before proceeding, the officials said.

Who is FBI Director James B. Comey?

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Scenes from the career of the bureau’s head.

Even after Comey received the desired information, major questions still remain — for instance, how many emails are related to Clinton or contain classified information. Since notifying Congress, Comey has drawn intense criticism from lawmakers in both parties as well as prominent former law enforcement officials for publicizing the investigation so close to the election when so little was known.

[Comey faces a firestorm of criticism over renewed Clinton email probe]

It is unclear what FBI agents have learned since discovering the emails in early October. But officials say they gained enough information from the email metadata to take the next step, seeking a warrant to review the actual emails. That legal step prompted Comey’s letter to Congress, which has made him a central figure during the stretch run of the presidential campaign.

“He needed to make an informed decision, knowing that once he made that decision, he was taking it to another level,” an official with knowledge of the decision-making process said.

Law enforcement officials on Oct. 3 seized the computer belonging to Weiner, who was under investigation for allegedly sending suggestive online messages to a teenage girl. As they examined his computer, investigators quickly stumbled on emails tied to Abedin. She and Weiner separated in August. Abedin, like Clinton, used an email address that was routed through Clinton’s private server.

Soon after the investigators found the new trove of thousands of emails, they notified the separate team of FBI agents in Washington that worked on the probe into Clinton’s private email server, officials said. Comey said in July that the investigation was complete and that he would recommend to prosecutors that no charges be brought.

After the agents on the Clinton case were notified in early October about the newly discovered emails, they in turn told FBI leaders about them.

At that point, the leaders did not believe they had enough information to make a decision about what to do next, officials said.

The senior FBI officials instructed the agents to do everything they could within legal limits to determine the relevance of the new emails, one official said. That review, including a closer examination of the email metadata, was an attempt to figure out the scope and volume of what the agents had found.

An FBI spokesman declined to comment.

In notifying lawmakers on Friday about the new investigative steps, Comey said he had been “briefed” about the newly discovered emails a day earlier but did not mention that he had first heard about them before that. The news media has widely reported that Comey was first told about the emails last week.

A formal briefing for Comey with the investigative team was held Oct. 27 at FBI headquarters. At that point, Comey was given a complete presentation of everything the team knew about the trove.

“It was a combination of assessments by the investigative team as to what it might be,” the official said.

Much was unknown about the contents and relevance of the thousands of emails. How many were to or from Clinton? Did any contain classified information? How many were duplicates of material the FBI had already reviewed? Was any of this significant to the Clinton email investigation that had been completed?

“At that point, there was no way for Comey to know if the [Clinton investigators] had already seen the emails before or if they were new, old or different,” an official said. “All of that was just unknown.”

But Comey and others felt there was enough information at that point to pursue a warrant, which would permit the investigators on the Clinton case to read the emails, officials said. They could not read them without legal permission because the emails had been discovered in the separate criminal probe involving Weiner.

[The Clinton email probe: Questions and answers]

When Comey and the officials decided to seek a warrant, they knew that would involve more people, both at the FBI and the Justice Department. Comey was concerned that the explosive information that they had to renew the Clinton investigation would leak out.

“It could not be done in secret,” an official with knowledge of the investigation said. “It’s a volatile subject and a major topic in the presidential campaign.”

But the overriding factor in Comey’s decision was that he felt he had to tell Congress what he was doing because he had testified under oath this past summer and “told Congress and the world” that the Clinton email investigation was complete, and now that was no longer true, an official said.

Then, Comey had to figure out what to say to lawmakers, when he knew so little. He wanted the letter to be accurate and “circumspect,” the official said.

“He wanted it to be carefully, thoughtfully done and say no more than his investigators knew,” the official said.

After the formal briefing, staffers in Comey’s office contacted senior officials at the Justice Department to notify them about the director’s decision. The next day, Comey sent his letter.

Two officials familiar with the case said it is unclear whether investigators will be able to conclude their review of the new emails before the election.

President Obama addressed the controversy in an interview posted Wednesday by NowThis, saying, “I do think that there is a norm that when there are investigations we don’t operate on innuendo, and we don’t operate on incomplete information, and we don’t operate on leaks.”

“When this was investigated thoroughly last time, the conclusion of the FBI, the conclusion of the Justice Department, the conclusion of repeated congressional investigations was she had made some mistakes but that there wasn’t anything there that was prosecutable,” Obama said.