BEIJING - The death toll in a massive landslide in north China rose to 23 Tuesday, as rescuers battled through the night to clear debris in an apparently fruitless search for survivors, state media reported.

The landslide occurred early Monday in Shanxi province's Zhongyang county, engulfing six makeshift homes where the families of migrant coal miners were living, state news agency Xinhua said.

Reports initially said three people were killed and 20 missing, but the toll steadily went up as more than 300 rescue workers uncovered body after body through the night, it said.

An investigation has been launched into the cause of the landslide, which occurred near the mine where the workers were employed.

Shanxi is the centre of China's coal mining industry, which is notorious for its poor safety record.

Official figures show that more than 3,200 workers died in collieries last year, but independent labour groups say the actual figure could be much higher because many accidents are covered up to avoid costly mine shutdowns.