US Homeland Security Chief Michael Chertoff said on Monday he hoped to work out an accord with the EU Commission to release more information on travelers before planes take off rather than while they are in the air.

"We have to develop a systematic approach to screening that is compatible on both sides of the Atlantic," Chertoff told a meeting of the European Policy Centre and German Marshall Fund.

"(An approach) that takes advantage of modern technology, provides maximum protection of sensitive traveler information and gives a real sense of confidence that we are screening out those with evil intent," he said on his first trip to Europe since taking office as head of homeland security in February.

US security concerns have caused two transatlantic flights to be diverted over the past two weeks.

The United States is trying to get key information on air travelers bound for the country up to an hour before their flights depart. Current rules require the data to be transferred 15 minutes after the flight departs.

Airlines check the names of passengers against the list before they are allowed to board. After the flight departs they send more complete personal data to the Department of Homeland Security for checks against no-fly lists and criminal databases.

If a passenger's name matches one on a watch list, the United States can order the plane to turn back or divert.

The US Congress has told the department to find a way to check passengers going to the United States against the no-fly lists before the flight departs.

Chertoff said last week he hoped the 25 member EU would provide the information 30 to 60 minutes before take-off. Many people would probably agree to hand over the data before departure to prevent their plane from being diverted or turned around, he said.

Screening of passengers must go beyond simply providing names and instead rely on biometric identification such as iris scans, he said. "Names can be changed, identification documents can be forged. But biometric identification can help reduce that type of fraud and protect the identity of the visa holder by making it much more difficult to impersonate someone," he said.

He also said advances were being made in the inspection of materials at ports but further research was needed.

The executive EU Commission and the United States struck a deal last year to give the United States access to even more detailed passenger information, but the European Parliament has challenged that agreement, citing privacy concerns.

Chertoff is in Europe to speak to Dutch and British officials as well as EU leaders. He has already visited the Netherlands and is due to visit Britain later this week.

He said earlier that a pilot project expected to start in the autumn at New York's Kennedy and Amsterdam's Schiphol airports would involve travelers passing border controls with a biometric card and undergoing no more questioning or screening.

"We are talking about a voluntary system using people who want to be in a green lane... if they are willing to volunteer to have a certain amount of background checking and to submit a biometric, like a fingerprint," Chertoff told reporters.