US Homeland Security officials proposed on Wednesday making airlines transmit passenger names and other information to the government before an international departure, a change designed to keep suspected terrorists off US-bound flights.

If approved, the security initiative would reverse the current policy of requiring that manifests for flights originating in foreign countries be transmitted shortly after takeoff.

The proposal seeks to improve and streamline security as well as end the inconvenient and sometimes embarrassing practice of ordering flights diverted or turned around if manifest information raises suspicion with US authorities or is incomplete.

The change also should relieve airlines operating international service of having to screen their passengers against security watch lists maintained by the US government, homeland security officials said.

"Our priority is to keep terrorists out of the United States by preventing them from boarding international flights," Homeland Security Secretary Michael Chertoff said in a statement.

Authorities are concerned that someone suspicious who is allowed to board an aircraft could plant or retrieve a bomb or other weapon before takeoff or in the early stages of a flight.

The proposal would apply to all international flights. Currently all overseas flights originating in the United States must transmit passenger information before departure.

Under the new plan, carriers would have two options to electronically send information to customs authorities. They could transmit the entire manifest 60 minutes before departure or relay data as passengers check in up to 15 minutes before the plane leaves.

Customs officials would have to clear each name before an airline would allow a passenger to board. The proposal would also change the definition of departure from the point at which a plane leaves the ground to when it leaves the gate.

Homeland security officials said they worked with airlines on the plan but will get a better sense of which option they prefer during a 30 day public comment period on the proposal.

Officials believe big airlines will roll over their data during passenger check-in because they have the technology to do so. Smaller airlines will probably opt for the one-hour compliance time.

The change also would apply to commercial ships, like cruise lines, which would have to follow the 60 minute rule.