The name of a "known or suspected" security threat was caught by U.S. authorities before the plane on which he was flying was allowed to touch American soil on Wednesday, U.S. officials said.

A spokeswoman from the U.S. Transportation Security Administration (search) said the passenger, who was traveling on a French passport, "was a positive match with an anti-terrorism watch list."

"Homeland security made the match by checking data transmitted after the flight departed from London," the spokeswoman said.

The man, who was not identified by authorities, was a passenger on British Airways (search) Flight 175 from London to New York. The flight was three hours into its journey to John F. Kennedy International Airport (search) when it was diverted back to the United Kingdom after U.S. authorities spotted his name on the watch list.

Flight 175 arrived at London's Heathrow Airport (search) at around 5:30 p.m. and the passenger was met by London's Metropolitan Police.

After questioning, the passenger was released without charge.

The name on the list belongs to a suspect who has links to a Moroccan extremist group. A Homeland Security official had earlier told FOX News there was no reason to believe the passenger, who was traveling with a French passport, was not in fact the suspect on the list, but that a false-positive identification could not be ruled out.

The TSA has determined that British Airways followed proper security procedures.

It was only after the plane took off that the airline sent the passenger manifest to U.S. Customs and Border Protection (search), which matched the name against the list. A U.S. official told FOX News that Britain last updated its no-fly list in December, when the United States added his name to its own, meaning the suspect's name simply did not appear on the British rolls.

A Homeland Security official told FOX News that the passenger's name was caught when the flight was already in progress because airlines are required to provide passenger manifests for international flights 15 minutes after takeoff. Washington wants to change that practice so the manifests are sent beforehand.

"It really underscores the importance of Homeland Security assuming the responsibility for administering these airline passenger watchlists," TSA spokeswoman Yolanda Clark said.

The remaining 238 passengers were re-screened, and the plane took off again for New York, British Airways spokesman Honor Verrier said.

Currently, the airlines administer the no-fly lists, but the TSA is testing a new computer-based screening system that would be administered by the government.

FOX News' Catherine Herridge and The Associated Press contributed to this report.