DAR ES SALAAM -- Three foreigners, from Brazil, Kenya and India, and eight Tanzanian technicians were killed early Thursday, and two others seriously injured, following an explosion at a sugar factory in Morogoro region in eastern Tanzania, a local official said.

Shaban Marujugo, Morogoro region commander for the Tanzania Fire and Rescue Force, told Xinhua over the phone that the blast occurred at 1:00 a.m. local time (2300 GMT Wednesday) at the Mtibwa sugar factory in Kilombero district.

The blast hit the control room, where technicians were testing one of the newly fixed heating systems for sugar production, Juma Ramadhan Palamba, an electrician at the plant, told Xinhua, also via phone.

The explosion occurred after a pipe that releases steam into a boiler busted, Palamba said.

The newly fixed system was scheduled to start operations on Friday, he said, noting that he escaped unhurt because he went out of the control room to answer a phone call at the time of the explosion.