A New York imam pleaded not guilty Monday to charges he lied to FBI agents about warning off an alleged Al-Qaeda associate plotting a bomb attack around the anniversary of 9/11, a court official said.

Ahmad Wais Afzali, 37, was arraigned in a Brooklyn court and allowed to go free on bail set at 1.5 million dollars, a spokesman for the prosecution told AFP.

Arrested in September, Afzali was charged two weeks ago with lying to FBI agents about tipping off Najibullah Zazi, an Afghan immigrant accused of conspiring to bomb New York around the anniversary of the September 11, 2001 attacks.

According to prosecutors, Afzali telephoned Zazi, 24, to warn him that he was being watched by the Federal Bureau of Investigation.

Zazi was arrested in September on suspicion of carrying bomb-making instructions in his laptop and shopping for bomb-making ingredients.

Prosecutors said Zazi had received training about explosives in Peshawar, Pakistan, a hotbed of Al-Qaeda activity.