HARBIN - At least seven were killed and 11 others remained trapped after a flood occurred in a colliery early Wednesday in northeast China's Heilongjiang Province, rescuers said.

Twenty-eight miners were working underground when the accident happened at about 7 am, at a shaft of the Junyuan No. 2 Coal Mine located in the city of Hegang, said an official with the rescue headquarters of the accident.

So far, 10 have managed to escape on their own or with help, and rescuers are still searching for the trapped.

The cause of the accident is being investigated.