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BEIJING - An explosion in a nightclub in northeast China killed 25 people and injured 33, state media reported as investigators sought to pin down the cause.

The blast hit an entertainment club in Benxi county, Liaoning province, at about 9pm on Wednesday (1am NZT Thursday), the China News Service reported.

After authorities finished rescue efforts on Thursday, the official Xinhua news agency reported the death toll, citing province officials, but it did not say how badly hurt the injured were or explain the cause of the explosion.

A county official at the scene told Reuters that investigators were trying to work out whether the blast was accidental or deliberate.

"It's too early to announce any conclusions," said the official, who gave his surname a Chi.

The Communist Party chief of Liaoning province, Li Keqiang, ordered harsh punishment of anyone found to be responsible for the explosion, the news service said.

Also on Wednesday night, a fire swept through a cinema complex in Hengyang city in central Hunan province. Xinhua reported that one person died.