Beijing ? An explosion at a coal mine in northeastern China left 40 dead and another 138 missing, state media reported today.

A total of 220 miners were underground when the blast occurred late Sunday at the Dongfeng Coal mine in Qitaihe, a city in Heilongjiang province, the official China News Service said, citing the local coal mine safety administration.

It did not give the cause of the blast and said it was under investigation.

The official Xinhua News Agency said earlier that 30 were dead and 149 were missing.

It was not immediately clear why the numbers were different. A man who answered the telephone at the coal mine said officials were too busy to talk and hung up.

Xinhua said rescue work was continuing.