Najibullah Zazi has admitted that he planned to carry out a "martyrdom" attack on the New York City subways.

The Afghanistan native pleaded guilty in Brooklyn this afternoon to conspiracy to use weapons of mass destruction and supporting terror.  The Associated Press reports that he also pleaded guilty to conspiring to commit murder in a foreign country. He will face a possible sentence of life in prison without parole at a hearing slated for June.

The former Denver airport shuttle driver says he received training from al-Qaida in Pakistan and was prepared to die to quote "bring attention to what the U.S. military was doing to civilians in Afghanistan." 

Law enforcement officials accused Zazi of receiving explosives training in an Al Qaeda terror camp in Pakistan. He reportedly told prosecutors that he did have bomb-making components while on the way to New York City last year, but that he got rid of them along the way.

At the time of his arrest, Attorney General Eric Holder said the Zazi case was the most serious terrorism threat since the 9/11 attacks.

UPDATE: This story has been changed to reflect Zazi's guilty plea.