Two top al-Qaeda leaders ordered an attack on the New York subway system, in what authorities call one of the most serious terrorism plots on American soil since the Sept. 11, 2001, attacks, before they were apparently killed in U.S. missile strikes, a criminal defendant in the plot and law enforcement officials said Friday.

Zarein Ahmedzay, a New York City taxi driver, pleaded guilty to federal charges in a Brooklyn courtroom, testifying that he plotted suicide attacks in Manhattan in September, during the month of Ramadan. Ahmedzay said he conspired with Najibullah Zazi, an airport shuttle bus driver who had earlier pleaded guilty in the plot. Federal officials have said their plan was in its final stages when it was thwarted.

Ahmedzay, 24, told a judge that he, Zazi and another person met along the Pakistan-Afghanistan border in August 2008 with two top al-Qaeda officials, who ordered them to return to the United States and conduct attacks. The primary target was the New York City subway, where the group planned to detonate potent explosives.

Federal prosecutors identified the officials Friday as Saleh al-Somali, al-Qaeda's head of international operations, and Rashid Rauf, a key operative for the terrorist group.

Authorities have identified Rauf as one of the planners of a 2006 plot to blow up simultaneously as many as 10 U.S.-bound passenger jets with liquid explosives hidden in carry-on luggage. He is believed to have been killed by a missile fired by an unmanned U.S. drone aircraft in November 2008.

Somali, a senior al-Qaeda planner, ran its operations outside the Afghanistan-Pakistan region. He was apparently killed in a similar strike in December, U.S. counterterrorism officials have said.

Background:
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