HARBIN, Sept. 2  -- Three inmates are at large after killing a guard in a detention center in northeast China's Heilongjiang Province early Tuesday morning, the local government told Xinhua.

The incident happened at around 4 a.m. in Yanshou County near the provincial capital city of Harbin, according to the city's public security bureau.

The bureau has sent a task force to Yanshou to investigate the case but gave no further details.