A fireworks blast killed one person and left two missing in a residential building in south China's Guangdong Province Saturday, local authorities said Sunday.

The blast, which also injured 11 people, occurred at about 4:30 p.m. in a fourth-floor apartment in a residential building in Dongguan City, a spokesman with the city government's information office said.

The blast destroyed the walls surrounding the apartment, leaving only the supporting pillars, said a witness surnamed Xu, who lives in a neighboring building.

"I was watching TV when I heard the two bangs, which shattered my windows," said Xu.

The injured were taken to local hospitals and their conditions were stable, said the city government spokesman.

An initial investigation showed that raw materials for fireworks, which the apartment owner possessed illegally, caused the explosion, he said.

Police are still investigating and no further details are available yet.

Residents whose apartments were damaged by the blast and those waiting for safety checks on their homes were evacuated from the building to relatives' homes or nearby hotels, said the spokesman.