The federal government's plans to develop a computer program to screen airline passengers came under assault yesterday from the European Union, civil libertarians and the Bush administration's own budget office, with each suggesting the government should resolve serious legal, privacy and operational questions before moving forward with the program.

The Transportation Security Administration is testing a passenger-screening computer system with Delta Air Lines that would provide the government with more information about each passenger who makes an airline reservation, including an individual's personal and financial data.

The system, which is supposed to replace a current computer program that assesses risk based on one-way tickets and other outdated measures, would then assign a color code to each passenger indicating the threat risk they present: green, yellow or red.

Civil liberties groups have raised questions about the program, saying they want to know the specific information the government intends to collect, but the TSA has not provided much detail.

Yesterday, the European Union said it is concerned that the TSA's new program would conflict with EU laws protecting personal data because the computer program would screen foreigners who fly to the United States. A program "with access to data banks in the European Union would raise issues with EU data-protection legislation," said a source with the European Commission. "The U.S. government should consult with us on such matters in order to avoid potential conflict."

In addition, the Office of Management and Budget raised questions as to whether the new computer program would be effective in fighting terrorism.

"I have a huge spotlight on that project," Mark A. Forman, associate director of the budget office, told the House Committee on Government Reform's subcommittee on technology and information policy, according to the Associated Press. "If we can't prove it lowers risk, it's not a good investment for government."

A TSA spokesman said the agency is aware of the concerns and has a long way to go in developing its Computer Assisted Passenger Prescreening System II, or CAPPS II.

"We are working together on this and we have a dialogue that seeks to respond to the issues and concerns raised during that process," said TSA spokesman Robert Johnson.

Johnson said the TSA has a meeting scheduled with the administration's budget office later this week to continue discussing the concerns.

Separately, several liberal and conservative organizations, including the American Civil Liberties Union, Americans for Tax Reform, the Center for Democracy and Technology, and the Eagle Forum, urged lawmakers yesterday to ask the TSA tough questions about CAPPS II before it moves ahead.

"Although the TSA's recent outreach to stakeholders is welcome, Congress should not allow the TSA to develop unilaterally a tool that could invade individual privacy and brand innocent airline passengers a security risk without meaningful review," the organizations wrote in a letter to the House Select Committee on Homeland Security.

Researcher Margaret Smith contributed to this report.