Security is being tightened for some U.S.-bound flights following the deadly crash of a Russian jetliner in Egypt last weekend.

The Department of Homeland Security announced the move today without naming which foreign airports are involved.

The agency said an additional layer of security will include expanded screenings for commercial flights to help keep the traveling public safe.

Homeland Security Secretary Jeh Johnson called it a precautionary move as DHS continues to work closely with domestic and international partners to evaluate the cause of the Russian plane crash. (Metro Networks Inc.)