Rescue workers using floodlights searched into the night for bodies at a Bangkok munitions factory reduced to rubble this morning by a chain of powerful explosions. The government redaio reported that 38 persons were confirmed killed and more than 350 injured in the blasts.

Broadcasts said investigators did not yet know the cause of the explosions, which also destroyed adjacent wooden houses occupied by factory workers and their families and broke windows hundreds of yards away.

Operated by the Royal Thai Army, the factory had produced M16 rifle ammunition, hand grenades and other munitions. It was built as part of efforts to make Thailand less dependent on military supplies from abroad.

The first detonation was heard about 10:30 a.m. and apparently set off explosives stored around the two-story factory.

"It was just like a B52 bomber strike, only longer," said Thawatchai Jaengcharoen, 34, a worker who formerly served in Vietnam.

Thawatchai, his wife and two of his three children were injured as they ate breakfast in front of their house, 50 yards from the factory. The house was heavily damaged, he said.

Work normally stopped on Sundays, he said. But today the machines were being operated by a special 10-member team under the supervision of Army officers.

"They were all killed," Thawatchai said in an interview at Bangkok's Ramathibodi Hospital.

Heard around the capital, the explosions sent a mushroom cloud of smoke high into the air. As victims fled the scene in panic, fires touched off smaller blasts sporadically.

Prime Minister Prem Tinsulanond visited the site this afternoon. Officials planned a full investigation. Already Thai newspapers have published sensational accounts of the explosions amid speculation that infiltrators -- perhaps from Vietnam -- were responsible.