The pace of terrorist arrests across western Europe has picked up since the attack on the offices of Charlie Hebdo in Paris, signifying either an escalation by al-Qaeda or more proactive policing by authorities.

The latest sweep occured in Italy, where Italian police arrested 10 suspects and are looking for 8 more connected to a plot to attack the Vatican.

Reuters:

Some of the suspects, who are all Pakistanis and Afghans, were arrested in early morning raids across Italy. Police burst into the home of the group's suspected spiritual leader, in the northern city of Bergamo, a video released by them showed.

Though the 18 suspects were plotting attacks mainly in their native countries, phone taps suggest the Vatican was also a target, said Mauro Mura, chief prosecutor of the Sardinian city of Cagliari, where the group had its headquarters.

Mura said officials had indications of a possible plot for an attack against the Vatican in 2010 by members of the group, who had continued to operate across Italy for years after that.

He said there were indications of a plan for a suicide attack in a crowded place. Italian officials have for years feared a possible attack by militants in St. Peter's Square and have increased security there.

In the tapped conversations, the suspects discuss "a big jihad in Italy", added Mario Carta, head of the police unit on the case. They reference the word "baba", which could mean the pope, Carta said.

"We don't have proof, we have strong suspicion," that the Holy See was a possible target, he told reporters at a press conference.

Carta told Reuters by telephone that the group in subsequent years "realised that we were watching their movements".

Vatican spokesman Federico Lombardi said the hypothetical attacks were in the past, and that the new disclosures were not a matter for concern.

But Vatican Secretary of State Cardinal Pietro Parolin said: "We are all afraid because we don't know what can happen."

Italy, like other European countries, has been on heightened alert for possible terrorist schemes in the wake of the January attack on French satirical magazine Charlie Hebdo.

European capitals are particularly worried about possible "sleeper" militants, apparently living normal lives in their countries, who may at some point in the future be activated to stage attacks at home or abroad.

Eighteen terrorists and wannabe terrorists running around Italy for at least 5 years?  Raids on terrorists in recent months in Belgium, France, Germany, Great Britain, and several other countries, not to mention Australia and the U.S., reveal a frightening truth: there are more jihadists among us than we have been led to believe, and their plotting is far more active than we thought.

To paraphrase Dick Cheney: we have to be successful in stopping them 100% of the time, where they have to get lucky only once.  So far, the luck of the West is mostly holding, but for how long?  A suicide bomber or two in St. Peter's square on a Sunday during the pope's weekly address could kill hundreds. 

Somewhere, a clock is ticking, and authorities in the West are racing to stop an attack before they run out of time.