Washington ? The federal government’s latest attempt to improve security checks of airline passengers is prompting privacy concerns.

The Transportation Security Administration has ordered U.S. airlines to turn over data on millions of passengers so the government can test the plan. Called “Secure Flight,” it compares passenger records — from credit card numbers to addresses — with names on terrorist watch lists.

Though Secure Flight does not apply to foreign airlines, the names of European passengers who have flown on U.S. airlines probably are among those to be tested.

Peter Schaar, chairman of a group of European data commissioners that advises the European Commission, said Secure Flight might violate European privacy laws.

“Nobody knows how it works,” Schaar said.

Schaar said European data protection commissioners had “huge concerns” about an earlier U.S. effort to conduct computerized screening of passengers. That effort was scuttled because of fears the government would have access to too much personal information.

European data privacy commissioners will meet next week to discuss the situation, said Schaar, who is Germany’s commissioner. He also plans a January trip to Washington to visit Homeland Security officials, who oversee the TSA.

TSA spokesman Mark Hatfield said Friday, “We work closely with the Europeans to ensure mutual satisfaction with data handling protocols.”

The Homeland Security Department ordered 72 U.S. airlines to turn over data by Tuesday so the system can be tested, and many are expected to do so.

American Airlines, the nation’s largest, said Friday that it had turned over the data for passengers who flew in June, as the TSA ordered. “We will comply with all applicable federal laws and regulations,” said spokesman John Hotard.

JetBlue also intends to give the TSA its passenger records, said spokesman Todd Burke.

But if the European Union determines that Secure Flight violates its privacy laws, airlines would be put in a bind: If airlines give passenger records to the government, they risk fines from the European Union for violating EU privacy laws. And if they obey the European Union, they risk fines from the United States.