PARIS -- Police tightened security Saturday following an explosion in one of the capital's most exclusive restaurants that seriously injured a Frenchwoman and slightly hurt 11 other diners, including five Americans.
Officials said police will be on special alert during Christmas and added that a new anti-terrorist plan was in operation at France's two international airports.
The plan was meant to safeguard against booby-trapped truck bombings like those perpetrated against French and U.S. troops in Lebanon, they said.
Police searched through the rubble left by a device that exploded in Le Grand Vefour Friday night, leaving a 15-inch crater in front of the establishment, located near the Louvre museum in central Paris.
No one claimed responsibility for the attack, they said.
About 15 people were in the usually crowded three-star 18th Century restaurant when a device placed in an outer air duct exploded, shattering windows and sending glass and metal flying through the dining room.
A 38-year-old Frenchwoman, Maurine Chretien-Rudetzki, who was at a windowside table, was hit by flying glass and metal. She was described in critical condition after doctors amputated her leg.
Police identified the injured American tourists as Monica Healy, 33, of Washington, D.C.; Nancy Newman, 29, address unknown; and George Hager, 33, Susanna Hager, 31, and Bruce Hager, 29, all of New York.
Another French diner who was not identified suffered burns, and Japanese tourist Saruko Nabuo was hospitalized. A second injured Japanese tourist was identified as Furruta Yuki.
Another three persons suffered minor cuts and abrasions that were treated by medics.
Witnesses said the blast sent thick smoke through the rooms of the restaurant. Police first thought the explosion was caused by gas.
The restaurant is owned by one of the country's top chefs, Raymond Oliver. The daughter of the 74-year-old chef quoted him as saying: 'I am ruined. My clients trust me and this had to happen to me as I reach the end of my career.'
The elegant rooms facing the Palais Royal gardens are a favorite dining spot for wealthy French and visiting tourists.
On Nov. 20, a grenade was lobbed into the l'Oree du Bois restaurant in western Paris, injuring 30 people. No one claimed responsibility for that attack.