The US government is requiring international air carriers to provide security officers on some flights over the United States, as part of its efforts to enhance air safety security.

"We are asking international air carriers to take this protective action as part of our ongoing effort to make air travel safe for Americans and visitors alike," Homeland Security Secretary Tom Ridge said in a statement issued on Monday.

The directive, effective immediately, will further enhance security on commercial and cargo aircraft flying to, from and over the United States, the Department of Homeland Security said.

The move will apply to specific flights "based on specific information" whenever it surfaces, said Homeland Security spokesman Dennis Murphy.

The US government raised the national threat alert to the second-highest level on Dec. 21, saying terrorists abroad anticipated attacks that would "rival or exceed" the Sept. 11, 2001 attacks.

Intelligence reports indicated "al Qaida continues to consider using aircraft as a weapon," Ridge said while announcing the raising of the threat alert level.

Air France canceled six flights between Paris and Los Angeles during Christmas holidays after "credible" threats information were provided by US officials.

(Xinhua News Agency December 30, 2003)