The federal government's latest attempt to improve security checks of airline passengers is prompting privacy concerns here and abroad.

The Transportation Security Administration (search) has ordered U.S. airlines to turn over data on millions of passengers so the government can test the plan. Called "Secure Flight," (search) 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 probablyto be tested.

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

"Nobody knows how it works," Schaar said.

Schaar said European data protection commissioners had "huge concerns" about the U.S. government's first attempt at computerized screening (search) 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.

The Homeland Security Department ordered 72 U.S. airlines to turn over data by Tuesday so the system can be tested.

If the European Union should determine that Secure Flight violates its privacy laws, airlines would be put in a bind. If they should comply with the TSA's orders, they would risk being fined by the European Union for violating EU privacy laws. If they should obey the European Union, they risk fines from the United States.

Airlines have been meeting to decide what to do, said Doug Wills, spokesman for the major airlines trade group, the Air Transport Association.

"Airlines are still reviewing the requirements on the operational and privacy details," Wills said.

Meantime, the American Civil Liberties Union believes the Secure Flight test may violate a U.S. law passed last month. It forbids the Homeland Security Department from spending money to test whether passengers' identity can be verified using commercial databases until the Government Accountability Office has assessed the plan.

In its order to the airlines, the government said it will "separately test the use of commercial data" to see if it helps to identify passengers better.

The ACLU has drafted a letter to Homeland Security Secretary Tom Ridge asking for assurances that testing won't begin until after the GAO review, which probably will take months.

"Our goal is to force DHS to confront the issue," said Barry Steinhardt, an ACLU lawyer.

A $2.9 million contract was awarded to IBM Corp. on Wednesday to conduct the test.

A telephone call to TSA seeking comment was not immediately returned