Beijing (CNN) An explosion at a coal mine in northern China's Inner Mongolia autonomous region killed 32 people on Saturday, the state-run news agency Xinhua reported.

Of the 181 people working in the mine at the time of the blast, 149 managed to get above ground and survive, the news agency added.

Authorities earlier reported 17 deaths and an undisclosed number of persons still trapped in the mine, but Xinhua reported everyone trapped is now believed to have died.

The explosion occurred around noon at a mine operated by the Baoma Mining Co. in the Yuanbaoshan district of Chifeng city, Xinhua reported.

An investigation into what caused the blast is still ongoing, but Xinhua reported Sunday that "It has been confirmed to be a gas explosion accident."