Federal officials believe that the fatal bombing of Pan Am Flight 103 required aid from a foreign government because of the complex preparations that had to have been involved, a top State Department official says.

"We don't believe terrorist organizations can pull off a Pan Am 103 without state support from somewhere," Clayton E. McManaway Jr., the department's associate coordinator for counter-terrorism, told Congress Tuesday.McManaway testified to the House aviation subcommittee, which was holding a hearing on aviation security. He did not provide the lawmakers with further details.

Congress has held several hearings on the security implications of the Dec. 21 explosion aboard the jetliner, which killed 270 people as it soared over Scotland. Authorities believe a bomb had been disguised as a radio-cassette player and placed in checked luggage.