REUTERS & AP

BOSTON A MASSACHUSETTS man charged with plotting to attack the Pentagon and the US Capitol with large, remote-controlled model airplanes packed with explosives has agreed to plead guilty, authorities said on Tuesday.

Prosecutors and defence attorneys have agreed to request a 17-year sentence for Rezwan Ferdaus on charges that he attempted to damage and destroy a federal building, and attempted to provide material support to terrorists.

Ferdaus, 26, of Ashland, Massachusetts, earlier pleaded not guilty to a total of six charges after his arrest in September 2011 after an undercover FBI investigation.

In exchange for the guilty plea, the government will dismiss the remaining charges.

A US citizen and a physics graduate from Northeastern University, Ferdaus was arrested after an FBI investigation during which he requested and took delivery of explosives, three grenades and six assault rifles from undercover FBI agents.

At the time of his arrest, Ferdaus had obtained one remote-controlled aircraft, a scale model of a US Navy F-86 Sabre fighter jet about the size of a picnic table, which he kept in a storage locker rented under a false name.

Authorities said the public was never in danger from the explosives and weapons, which they said were always under the control of federal officials during the sting operation.

The government had previously alleged that Ferdaus told undercover agents of his plans to commit acts of violence against the United States by decapitating its “military centre” and killing “kafirs,” an Arabic term meaning nonbelievers.

He was charged with planning to use three remote-controlled airplanes, each packed with five pounds of explosives, to blow up the Pentagon and US Capitol.

Counter-terrorism experts and model-aircraft enthusiasts said it would be nearly impossible to inflict large-scale damage of the kind Ferdaus allegedly envisioned using model plane because the aircraft are too small, can’t carry enough explosives and are too difficult to fly.

In 2010, already under surveillance, Ferdaus allegedly supplied 12 mobile phones rigged as electrical switches for improvised explosive devices to FBI agents whom he believed to be members of or recruiters for Al Qaeda.

Ferdaus’ attorneys suggested during a bail hearing in November that their client had mental health issues, and that his attack plan was “fantasy.” During a bail hearing in November, an FBI agent acknowledged that the FBI had received reports about bizarre behaviour by Ferdaus, including a report to Hopkinton police about one incident in which Ferdaus allegedly stood in the road not moving and appeared to have wet his pants.