Updated

A man who tried to ignite a shoe full of explosives aboard a jetliner Saturday was charged Sunday with the federal crime of assaulting a flight crew, as authorities warned airlines that would-be terrorists could be boarding planes with bombs hidden in their shoes.

The identity of the failed bomber, who tried to ignite explosives in his sneaker on a Boeing 767 jetliner bound from Paris to Miami, remained unclear.  He was listed in court papers Sunday as Richard C. Reid, the name on his British passport. French authorities identified him as a Sri Lankan named Tariq Raja. In London, Scotland Yard said they believed the suspect was a British national.

Reid, 28, was overpowered by the flight crew and a group of passengers, and the plane was diverted to Boston. Preliminary FBI tests found explosives in the sneakers Sunday.  Reid faces a maximum 20 years in prison if convicted.

The Federal Aviation Administration on Sunday ordered airlines and airports to guard against passengers boarding planes with explosives hidden in their shoes. Technology that detects traces of explosives on carry-on baggage can also be used to check passengers' shoes.

An initial court appearance was set Monday morning, the FBI said. Reid was being held under constant watch Sunday in a jail in Plymouth, according to Mike Seele, spokesman for the Plymouth County Sheriff's Department.

Officials at the British consulate in Boston have arranged to meet with Reid before Monday's hearing, a consulate spokeswoman said.

French police opened an investigation Sunday to determine how Reid eluded increased security measures at Charles de Gaulle airport outside Paris, where American Airlines Flight 63 took off Saturday.

Passengers on the flight said they had noticed the tall, ponytailed man standing alone and stone-faced before boarding.

"He had a blank look," Nicholas Green, a 27-year-old French trader, said. "The people who had seen him, remembered him."

During the flight, the suspect, who was sitting behind the wing in the coach section of the Boeing 767, lit a match, but put it in his mouth when confronted by flight attendant Hermis Moutardier, according to an FBI affidavit.

She told the captain and returned to see Reid with a match held to the tongue of his sneaker, then noticed a wire protruding from the shoe. She tried to grab the sneaker, but Reid allegedly pushed her to the floor, and she screamed for help.

Another flight attendant, Cristina Jones, intervened and the 6-foot-4 Reid bit her, authorities said.

"He bit Ms. Jones on the thumb and Ms. Moutardier threw water in his face," FBI agent Margaret G. Cronin said in the statement.

Passengers subdued the man, some taking off their belts to strap him into his seat, officials said. Two doctors used drugs from the airplane's medical kit to sedate him.

The plane, carrying 183 passengers and 14 crew members, was escorted to Logan International Airport by two F-15 fighter jets.

Since Sept. 11, some pilots have urged passengers to attack anyone who tries to interfere with the operation of a plane. On Oct. 8, Edward Coburn, 31, was subdued by passengers after he tried to storm the cockpit of an American Airlines flight from Los Angeles.

Passengers on one of the airliners hijacked on Sept. 11 are believed to have fought their hijackers and caused the aircraft to crash in Pennsylvania instead of into an apparent Washington target.

The U.S. Attorney's office in Boston said Sunday that preliminary FBI tests showed "two functional improvised explosive devices" in the man's shoes, described by a passenger as hightop sneakers.

"There will be further tests to determine exactly what he had," said a federal law enforcement official, speaking on condition of anonymity.

Logan officials described the substance as consistent with the military plastic explosive C-4.

In Washington, Sen. Richard Shelby of Alabama, senior Republican on the Senate Intelligence Committee, said the FBI told him in a briefing Sunday there were explosives in the suspect's shoes.

"This is taken very, very seriously," Shelby said on CBS-TV's "Face the Nation." "From what I've observed, this man was trying to blow himself up, blow the plane up. Is this part of a widespread deal or is this guy acting alone? We don't know yet."

Sunday's FAA directive followed a similar warning to airlines on Dec. 11 that potential hijackers might try to smuggle weapons in their shoes. Officials wouldn't say what intelligence prompted the warning.

French authorities said Reid had tried to board the same flight Friday but was turned away after raising suspicions.

French police said the suspect -- who also has gone by a third name, Abdel Rahim -- was given permission to board after intensive questioning, but by then had missed Friday's flight. He had only one small bag with him and said he was traveling to Antigua to visit relatives, police said.

After Reid was taken into custody at Logan, the other passengers spent 10 hours being searched and questioned. Most later boarded another plane to Miami, which landed early Sunday.

"Some thought this was a terrorist attack," said Geoffrey Bessin, a New York-born software designer who lives in France. "A lot of others thought it was taken care of, and nothing bad happened, so let's go back to our movie."

Logan was the airport where two planes departed Sept. 11 before they were hijacked and crashed into the World Trade Center in New York.

In the aftermath of the attacks, acting Gov. Jane Swift fired airport security chief Joseph Lawless. Later, Virginia Buckingham resigned as executive director of Massport, which runs Logan, amid promises by state officials to improve security.

The Associated Press contributed to this report.