An American Airlines aircraft flying from Paris to Miami was diverted to Boston last night after aircrew tackled a passenger of Arab appearance as he tried to set off what appeared to be plastic explosives packed into his shoes.

The plane, carrying 185 passengers and 12 crew, was escorted into Boston's Logan airport by two F-15 fighters and a quantity of the suspected explosive was taken away for analysis by the FBI. A Massachusetts Port Authority spokeswoman said that there were holes drilled in the shoe's heel "and there looked to be a detonator wire, and the substances consistent with the explosive C-4".

The man was travelling on an apparently false British passport and this, and his success in getting explosive on to a plane, will raise serious questions about the international anti-terrorism effort.

Tom Kinton, director of aviation at Logan International airport in Boston, told a news conference that flight attendants and other passengers had "tackled" the man. Kinton said the man had been carrying "enough improvised explosives to do damage".

He said a flight attendant had approached the man when he lit a match in mid-flight and attempted to light the explosive. "The flight attendants became alerted to the smell of sulphur... and got into a wrestling match in an attempt to stop this action," Kinton said. Flight attendants were hurt during the struggle, including one who was bitten by him.

The man's British passport, issued three weeks ago in Belgium in the name of Richard Reid, was almost certainly bogus.

A Foreign Office spokeswoman said: "We are aware that a UK citizen has been detained in the United States. The details are a matter for the US authorities. We are seeking normal consular access as we would with any UK citizen."

White House officials monitored the situation throughout the afternoon and President Bush received two briefings, spokesman Scott McClellan said. Administration officials also consulted with acting state governor Jane Swift's office.

Composition C-4 is a military plastic explosive. Its main ingredient is RDX, which is also used in fireworks.

The whitish, puttylike substance can be easily moulded by hand. It can be detonated if burned.

The explosive was used in the October 2000 bombing of the USS Cole in Yemen. The bombing of the American destroyer killed 17 US sailors and wounded 39.