Intelligence agencies have been warned that al Qaeda may be planning to attack air and rail travel in Europe in actions that may occur during the busy holiday travel season, CBS News has learned exclusively.
In separate interviews with Arab and other intelligence sources, CBS News has been told that the warnings come from interrogations of al Qaeda suspects who recently left Afghanistan and Pakistan.
"One suspect said plans for repeating the Heathrow attempt (a reference to the failed 'liquid bomb' plot interrupted in August) were all prepared. It is now a matter of taking action," said one Arab official who asked not to be named because he is not authorized to speak to the media. "Al Qaeda's strategy appears to be raising the pressure in Europe."
In a move that has been puzzling intelligence agencies, al Qaeda has been withdrawing well-trained Arab fighters from the mountains and battlefields of Afghanistan.
In detailed interviews with Arab diplomats, intelligence sources and Pakistani and western officials, Arab members have been leaving Afghanistan for the past six months while handing over its militant activities in Afghanistan to that country's resurgent Taliban movement.
The new information helps to shed fresh light on a key mystery at the heart of al Qaeda's decision, first reported by CBS News in September, to withdraw its Arab members, fighters and logisticians from Afghanistan.
Rohan Gunaratna, head of terrorism research at Singapore's Institute for Defense and Strategic Studies, and the author of "Inside Al Qaeda; Global Network of Terror," said "We have seen that several hundred, perhaps five to six hundred al Qaeda members who were located on the Afghan-Pakistan border, have now left."
an exceprt of Katie Couric's interview with counterterrorism expert John Brennan about CBS News' report.
Gunaratna adds that these al Qaeda members have returned "to their own home countries, particularly to Iraq, and also to other Middle Eastern countries such as Saudi Arabia and Yemen. We have seen a shift in Al Qaeda's thinking, in strategy."
Some of those who returned to their native countries in the Arab world and were caught have told investigators that the orders only specified al Qaeda's decision for the Arabs to depart Afghanistan.
The choice of a route was left to al Qaeda's local commanders in Afghanistan, according to information given by arrested suspects to their interrogators.
There is no consensus on the approximate numbers of Arabs who remain in Afghanistan, though Arab diplomats with responsibilities of tracking al Qaeda said, they suspect the number of active Arab fighters to run in the several hundreds in spring this year.
"Now, maybe there are a couple of hundred people left in Afghanistan, maybe a bit more or a bit less," said one unnamed Arab diplomat, who says it was "impossible to tell the numbers accurately. But there's enough information to say that al Qaeda's Arab component in Afghanistan is very scaled down."
The first indication of Afghan-based al Qaeda Arabs beginning to leave for Iraq came almost two years ago in deep background briefings given by Pakistani intelligence officials selectively to senior journalists. However, the movement had been long considered voluntary and more an act of choice by individual fighters or small groups of militants than a decision by Al Qaeda's high command.
A senior Arab diplomat said intelligence officers in his country thoroughly interrogated a group of men in their 20s and 30s who were caught earlier this summer after they returned from Afghanistan.
"The standard answer was: We don't know why we were told to leave. The orders were very specific — leave Afghanistan now without wasting much time." The diplomat spoke on the condition that neither his identity nor that of his country would be revealed.
Intelligence analysts and security sources say one reason why al Qaeda might feel confident in leaving the battlefield in Afghanistan largely in the hands of the Afghan Taliban is that the Taliban have shown new skill and ferocity in fighting U.S. and coalition forces.
"As you can see, the increasing ferocity of these attacks has put the spotlight more on the Taliban," said one western diplomat. "When we speak of Afghanistan these days, we talk mostly of the Taliban. In the Afghan context, al Qaeda is now talked about infrequently. Does this not tell you something about a trend, that maybe al Qaeda as we saw it once being led by its Arab fighters in Afghanistan, has become less of a reality as time goes by?" he asked.
"There is very little al Qaeda Arabs can do today in the Afghanistan/Pakistan theater," said Gunaratna. "Firstly, they will be spotted and they will be killed or captured. Second, today in Afghanistan Arabs are not really required to fight the coalition and U.S. forces, because the Taliban are very well trained and very well motivated."
Al Qaeda Arabs did provide suicide bombers — until now, a role Afghan Taliban were unwilling to undertake. In recent months, however, as Taliban propaganda videos have shown, Afghans have signed wills and undertaken suicide missions.
"There are two ways of looking at what is going on between the Taliban and al Qaeda," said a Pakistani security official who asked not to be named. "Either it's the case that the Taliban have become so strong by virtue of sharply rising ethnic 'Pushtoon' support to their cause that al Qaeda is overshadowed and wants to leave Afghanistan.
"Or it's a matter that al Qaeda sees its work for certain being carried forward by the Taliban and has therefore decided to leave. Whatever the motive, the fact is, al Qaeda's Arab wings seem to be leaving," the Pakistani official said.