France is searching for an Afghan on a U.S. list of suspected terrorists because someone with his name failed to board a Christmas Eve flight across the Atlantic that was canceled amid security fears, officials said Wednesday.

A passenger surnamed Hai was ticketed for Air France (search) Flight 68 to Los Angeles but did not show up, French officials said. They said investigators have not yet established whether the passenger is the Abdou Hai on a U.S. terrorism watch list or someone with the same name.

The name was one reason why security on trans-Atlantic flights was stepped up over the holiday season. In all, six Air France flights between Paris and Los Angeles on Christmas Eve and Christmas Day were canceled amid concerns members of the Al Qaeda (search) terrorist network might try to board planes.

Investigators said Abdou Hai is not known to French intelligence, and France's judiciary has not opened an investigation into him, meaning he is not now suspected of wrongdoing.

Secretary of State Colin Powell, asked at a news conference Wednesday if there was a single potential terrorist loose who is a source of grave concern, said he was "not aware of any one particular individual who is loose."

But Justice Minister Dominique Perben (search) confirmed Wednesday that French and European authorities were searching for someone who failed to show up for an Air France flight.

"We are looking for someone, but I can't say more," Perben told RMC radio. "What's important when someone doesn't take a plane is to know why he didn't take it," he added.

The Air France flights were canceled after U.S. intelligence told their French counterparts that Al Qaeda operatives would try to board the planes over Christmas, French officials have said.

Police questioned six people with tickets because their names appeared on a watch list of suspicious people provided by U.S. authorities. But French investigators determined that none of the six was a terrorist.

French police officials say errors in spelling and transcribing Arabic names have played a role in cases of mistaken identity with passengers.

Even after Christmas, U.S. authorities singled out a few people nearly every day as potentially suspect, Pierre Debue, director of French border police, told The Associated Press.

In all cases, the passengers either had the same names as suspects or did not turn up for the flights, he said. Investigators sought to determine why the no-shows did not fly, but did not turn up any cases of particular concern, he said.

"The people in question were found. The cases were clarified," he said. "We did not find anything serious."