A confusing, and disturbing, report from the Associated Press:

A powerful blast at a factory making explosives and weapons in southern Yemen killed at least 78 people on Monday after the facility was briefly taken over by Islamic militants and then looted by residents of the area, officials said.
Many women and children from the surrounding villages were killed in the explosion, which left some bodies blackened and burned, said medical and security officials in Abyan province. The blast appeared to be accidental but there was no word on the exact cause.
On Sunday, militants took over the factory and the nearby the town of Jaar, taking advantage of the country’s deteriorating security as an unprecedented wave of anti-government protests threatens the president who has ruled the impoverished and divided nation for 32 years.
The fighters took what they wanted and left. Later, locals entered the facility to loot it, said resident Walid Mohammed Muqbil. The factory makes munitions, Kalashnikov weapons and explosives used in road construction in the mountainous area.
Among the wounded, 27 people were in critical condition. Officials spoke on condition of anonymity because they were not authorized to speak to the press.
The factory was seized on Sunday by one of the many militant groups roaming Yemen’s largely lawless hinterlands called the Salafi Jihad.

Some 30 more were in critical condition. The loss of life is obviously tragic. But the desire of the group to raid the factory, and for locals afterward to loot it, show the dangerous sectarianism of Yemen. It’s also hard to imagine how such an accident could have been purely accidental.