Coal dust caught fire at the mine in the city of Qitaihe on Sunday while 221 miners were working underground, the official Xinhua news agency said. More than 70 miners were rescued, it said.

Outside the mine late on Monday, distraught family members sought answers. A stream of emergency vehicles travelled back and forth on the narrow road leading to the mine.

A 269-member rescue team was searching for the miners still trapped in the Qitaihe mine, and Li Yizhong, minister of the State Administration of Work Safety, told them to "spare no efforts" to save the workers, Xinhua said.

Unsafe mines

China's coal mines are the world's deadliest. Fires, floods, cave-ins and explosions are reported almost daily, and thousands of miners are killed every year.

Efforts to shut down dangerous mines have been complicated by the country's soaring demands for power to drive its booming economy.

Chinese President Hu Jintao and Premier Wen Jiabao urged officials to curb the "possible occurrence of big safety accidents which claim huge casualties and property losses", the state-run newspaper China Daily said on Monday.

The mine is owned by the Heilongjiang Longmei Mining Group Co, a conglomerate of four state-owned coal businesses in the province, Xinhua said.