The blaze at the four-story building in Shantou, Guangdong province, erupted around 9:20 p.m. on Tuesday, and was extinguished just after 10:00 pm, the local fire department said in a statement, AFP reported.
It comes after a huge blaze last month engulfed several high-rise residential towers in Hong Kong, neighboring Guangdong, killing 160 people.
“The building on fire was a four-story self-built reinforced concrete structure,” the Chaonan District Fire and Rescue Team said, adding that the blaze had affected an area of 150 square meters (1,600 square feet).
“Investigations into the cause of the fire and aftermath handling work are being conducted in an orderly manner,” it said.
Initial reports on Wednesday morning had said eight were killed, with four injured taken to hospital.
State media outlet Xinhua later said a total of 12 people had been killed.
The deaths come after China launched a campaign against fire hazards in high-rise buildings following the Hong Kong blaze last month.