Plans of a multi-city attack in Europe appear to be coming from a German al Qaeda base, U.S. and European officials tell ABC News. Two German nationals have been captured so far, and their claims about the planned attack have been supported by other “highly reliable sources,” according to officials. “There are several different sources, all confirming that there are plots afoot by al Qaeda central, that is to say the Osama bin Laden organization in Pakistan, to do attacks in Europe,” said Dick Clark, a former White House security official. Two Germans—Ahmed Siddiqui and Rami Makanesi—have been captured; Makanesi has been described as a “member of the Hamburg group” that seems to be the European base of the plot. While no plans to attack the U.S. have been uncovered, Clark says, that idea cannot be ruled out yet. Forty-five German nationals are currently being tracked.