Doctors and witnesses said many bodies were charred beyond recognition and other were believed buried under the debris inside the factory in the town of Jaar in Abyan province, where Al-Qaeda militants and mainly leftist southern separatists are active.

“This accident is a true catastrophe, the first of its kind in Abyan,” said one doctor at the state-run hospital. “There are so many burned bodies. I can’t even describe the situation.”

Hussein Al-Yafai, a local resident, told Arab News by telephone that rescuers were held back initially by intermittent explosions.

The series of explosions began around 9:30 a.m. as local residents rushed to the factory to loot ammunition left over from Sunday’s militant raid. “There were women among the victims," Hussein added.

Fifty injured people were taken to a local hospital and the critically injured to Aden. A burning cigarette butt carelessly thrown away by one of the looters likely triggered the explosions.

Abyan Gov. Saleh Hussien Al-Zuari ordered an investigation into the cause of the explosion.

A local source said militants also tried on Monday to break into a cement factory owned by a Saudi businessman in Abyan, but tribesmen prevented them from seizing the plant.

Clashes broke out in Jaar on Sunday between militants and the army, raising fears that chaos in Yemen would benefit Al-Qaeda while President Ali Abdullah Saleh's 32-year-old rule is in crisis.

Saleh is facing pressure from tens of thousands of protesters demanding his removal. On Monday, he sacked two army officials who defected to the opposition. They are Maj. Gen. Mohammed Ali Mohsen, commander of the Eastern Division, and Col. Thabit Jawas, commander of 15 Infantry Brigade.