Philip Pullella

Rome: The Vatican is on alert in case of an attack by Islamist militants against the city-state or Pope Francis, but officials are not aware of any specific plot, the head of Vatican security said in a rare interview.

"The threat exists. This is what has emerged from conversations with Italian and foreign colleagues," Domenico Giani told Polizia Moderna, the magazine published by Italian police, when asked if threats from Islamic State militants were credible.

"(But) at the moment I can say that we are not aware of any plan to attack the Vatican or the Holy Father," he added in the interview, published on the magazine's website on Monday.

A Swiss Guard on patrol at the start of the General Audience with the Pope, attended by thousands of people in St Peter's Square at the Vatican. Photo: Penny Bradfield

Islamic State militants have made threats against Catholic targets in Rome that have been given much space in Italian media.

Last month, in a video showing the beheading of 21 Egyptian Coptic Christians in Libya, one of the killers said: "Safety for you crusaders is something you can only wish for ... We will conquer Rome, by the will of Allah."

A website used by militants ran a photo montage showing the movement's black flag flying from the obelisk at the centre of St Peter's Square.

Executing Christians ... Members of the Islamic State (IS) jihadist group parade down a street in Libya's coastal city of Sirte. Photo: AFP

Giani said the alert level was "constantly high" in and around the tiny city-state, which sits inside Rome.

His force of some 130 agents, along with the more ceremonial Swiss Guard, protect most of the Vatican and the pope, while Italian police guard the exterior, as well as St Peter's Square.

Last month, in the wake of killings by Islamist militants in Paris and Copenhagen, 4800 soldiers were placed on the streets throughout Italy.

Protecting the Pope ... A member of the Swiss Guard closes the gate at the Arch of the Bells at St Peter's Basilica.Photo: Getty Images

Francis has several times condemned attacks by Islamic militants. On Sunday, he called for an end to their "intolerable brutality".

Reuters

Washington (AFP) - The United States' senior envoy to Europe alleged Wednesday that Russia had deployed "thousands and thousands" of troops to neighboring Ukraine.

Speaking to a congressional foreign affairs committee, Assistant Secretary of State Victoria Nuland also told US lawmakers that Russia was flooding eastern Ukraine with military hardware.

"Since December, Russia has transferred hundreds of pieces of military equipment, including tanks, armored vehicles, rocket systems, heavy artillery," Nuland said.

"The Russian military has its own robust command structure in eastern Ukraine... they are funding this war, they are fueling it and commanding and controlling it."

Nuland was not able to say exactly how many Russian troops were in eastern Ukraine -- where pro-Russian rebels are battling loyalist security forces -- but estimated the number to be "in the thousands and thousands."

On Tuesday, Western leaders, including US President Barack Obama, called for a "strong reaction" from the international community to any major violation of a ceasefire in eastern Ukraine as they sought to further pressure Russia over the conflict.

The leaders did not specify what a "major" break from the accord might be, nor what response it would provoke, but hinted at the possibility of further sanctions on Moscow.

But, in her testimony to the House Foreign Affairs Committee, Nuland suggested that Washington and its partners were ready to further tighten economic sanctions on Russia.

She also accused the Kremlin of violating the terms of a ceasefire deal agreed in Minsk.

"We have already begun consultations with our European partners on further sanctions pressure should Russia continue fueling the fire in the east or other parts of Ukraine, fail to implement Minsk or grab more land as we've seen in Debaltseve," she said.

Moscow denies any involvement in the conflict, which has cost some 6,000 lives over the past year, although it admits some Russian troops may have volunteered to fight with the rebels while on leave from their regular units.

Ferguson Officer Darren Wilson is pictured in this undated evidence photo. REUTERS/St. Louis County Prosecutor's Office

By Lisa Lambert and Carey Gillam

WASHINGTON/KANSAS CITY, Mo. (Reuters) - A U.S. probe found systemic racial bias targeted blacks and created a "toxic environment" in Ferguson, Missouri, but cleared a white officer in the fatal shooting of an unarmed black teenager there, Attorney General Eric Holder said on Wednesday.

The report said the St. Louis suburb overwhelmingly arrested and issued traffic citations to blacks to boost city coffers through fines, used police as a collection agency and created a culture of distrust that exploded in August when Ferguson Officer Darren Wilson fatally shot 18-year-old Michael Brown.

"This investigation found a community that was deeply polarized; a community where deep distrust and hostility often characterized interactions between police and area residents," Holder told reporters.

Brown's killing touched off a national debate on race, led to months of street protests and amplified long-standing complaints in Ferguson and across the country of police harassment and mistreatment of minorities. It also prompted Justice Department probes.

"Of course, violence is never justified," Holder said. "But seen in this context, amid a highly toxic environment, defined by mistrust and resentment, stoked by years of bad feelings, and spurred by illegal and misguided practices, it is not difficult to imagine how a single tragic incident set off the city of Ferguson like a powder keg."

Holder, who is stepping down soon as attorney general, called for wholesale and immediate change in the way Ferguson operates.

City officials said they would address the report later on Wednesday.

In a city where blacks make up about two-thirds of the population, they accounted for 85 percent of the total charges brought by Ferguson police, and more than 90 percent of arrests, Holder said, citing city records reviewed for the report.

Some police would compete to see who could issue the most citations to African-Americans, he said. Often the charges were trumped up, or fictitious. Police and city officials laced their emails with racist jokes, Holder added.

The city also looked to double its revenue in fines collected by the courts to a projected $3 million for its 2015 fiscal year, from over $1.3 million in 2010, he said.

"Ferguson police officers issued nearly 50 percent more citations in the last year than they did in 2010 – an increase that has not been driven, or even accompanied, by a rise in crime," Holder said.

NEW CALLS FOR POLICE CHIEF'S RESIGNATION

The report also led to fresh calls for Police Chief Tom Jackson and the city's mostly white leadership to step down.

"He absolutely should not have that job anymore," said St. Louis-area lawyer Brendan Roediger, who has helped represent some of those protesting police actions.

U.S. officials confirmed on Wednesday they could not find a civil rights reason to prosecute Wilson, who was not charged by a grand jury in Missouri for the shooting.

Lesley McSpadden and Michael Brown Sr., parents of the slain teen, said the decision not to pursue federal charges against Wilson disappointed them but the report could cause changes in Ferguson and other parts of the country.

"If that change happens, our son's death will not have been in vain," they said in a statement.

Jeff Roorda, a spokesman for the St. Louis Police Officers Association, said rather than blaming racial bias, there should be a "mature, frank conversation in the country about why kids like Michael Brown ... end up in deadly confrontations with police."

(Writing by Jon Herskovitz; Additional reporting by Lindsay Dunsmuir in Washington; Editing by Dan Grebler, Eric Walsh and Peter Cooney)