He had previously pleaded not guilty to charges he sought to join two former high school classmates from Queens in what prosecutors called three "coordinated suicide bombing attacks" on Manhattan subway lines.
A revised indictment unsealed last month added new charges alleging a high-ranking al-Qaida operative had recruited Medunjanin, Najibullah Zazi and Zarein Ahmedzay in 2008 to receive training from the terror network in Pakistan.
Zazi and Ahmedzay have pleaded guilty and are awaiting sentencing.
