Zazi Friends Plead Not Guilty to Terrorism

Updated at 2:03 p.m. ET

Two high school classmates of admitted terrorist plotter Najibullah Zazi were indicted Thursday in a foiled scheme to bomb New York City subways that a prosecutor said was directed by "al Qaeda leadership."

Zarein Ahmedzay and Adis Medunjanin, both 25, pleaded not guilty in federal court in Brooklyn to charges of conspiracy to use weapons of mass destruction, conspiracy to commit murder in a foreign country and providing material support to the al Qaeda terrorist network.

The three men were planning an attack on city subway lines last September under the direction of leaders of the al Qaeda terrorist network that would have been similar to the 2005 London subway bombings that killed more than 50 people, Assistant U.S. Attorney Jeff Knox said. They face a maximum penalty of a life sentence in federal prison.

Other "overseas" defendants will probably be named in the plot, Knox said.

"The facts alleged in this indictment shed further light on the scope of this attempted attack and underscore the importance of using every tool we have available to both disrupt plots against our nation and hold suspected terrorists accountable," Attorney General Eric Holder said in a statement. "This attack would have been deadly."

Sources tell CBS News Correspondent Bob Orr that the investigation remains open because it's unclear whether any other people allegedly knew about or supported the plot.

Authorities have told The Associated Press that Zazi was cooperating with federal investigators before his guilty pleas this week. Asked whether Zazi would testify against his client, Ahmedzay's attorney Michael Marinaccio said, "that's a likely scenario."

Medunjanin and Ahmedzay - who authorities say traveled to Pakistan with Zazi in 2008 - had already faced charges in the alleged plot to set off homemade bombs on Manhattan subway lines. Police said earlier this week that Zazi and two other bombers planned to attack rush-hour commuters to kill as many people as possible.

Ahmedzay and Medunjanin went to high school with Zazi in New York.

Zazi admitted Monday he received terrorism training during the trip when he pleaded guilty to federal charges. The former Colorado airport shuttle driver says he returned to the United States from Pakistan and planned to detonate bombs around the anniversary of the Sept. 11 attacks.

Both men had faced other charges in the case before Thursday.

Medunjanin has pleaded not guilty to charges he conspired to kill U.S. soldiers in Afghanistan. His lawyer, Robert C. Gottlieb, said earlier this week he didn't know if Zazi told prosecutors anything about his client but Zazi's decision to plead guilty "obviously affects the overall prosecution."

Ahmedzay has pleaded not guilty to charges that he lied to the FBI during the probe about places he visited during the 2008 trip.

Zazi's uncle, father and a Queens imam face lesser charges in the case.