Chicago, Dec 9 (IANS) Pakistani-American terror suspect David Coleman Headley has pleaded not guilty to charges that he planned the 2008 Mumbai terrorist attacks that killed 166 people and planned to launch an armed assault on a Danish newspaper.

Son of a Pakistani diplomat and an American socialite mother, Headley, 49, appeared Wednesday before US District Judge Harry Leinenweber in Chicago for an arraignment that lasted only about three minutes. He then was led away, guarded by a phalanx of federal marshals.

Headley was clad in the bright orange jumpsuit of a federal prisoner and wore a gray sweatshirt under it.

Leinenweber set Jan 12 for the next hearing in the case.

Meanwhile FBI Director Robert Mueller came to Chicago this morning for a briefing on the Headley case and is expected to leave afterward, Chicago Sun Times reported.