The bomb that destroyed Pan Am Flight 103 over Scotland was located in a front cargo hold in front of the wing, Transport Secretary Paul Channon said Tuesday.

Channon told the House of Commons that the fact that Semtex plastic explosives were probably used to make the bomb pointed to a highly organized terrorist group planting the device.The Boeing 747 exploded over the Scottish town of Lockerbie on Dec. 21, killing all 259 people on board and 11 people on the ground.

The Department of Transport's Air Accident Investigation Branch had narrowed "the area (of the bomb's location) to that of the No. 1 cargo hold just forward of the wing," Channon told lawmakers.

He said it was too early to tell where the luggage or article that contained the explosive originated.

"It is essential that we discover who put the bomb in the aircraft and how it got there. . . . The signs of the use of high-performance plastic explosive - which was very probably but not certainly Semtex - point to a well-organized and well-supported terrorist group," he said.

Western terrorist experts have said they suspect Semtex, an explosive made in Czechoslovakia, was used to sabotage the jumbo jet.

Although Czechoslovakia denies Semtex was used in the Lockerbie incident, it has promised to send experts to help in the investigation.