Nine miners were killed and 16 others injured in a coal mine accident in north China's Inner Mongolia autonomous region as the rescue wrapped up late Monday, officials said.

Rescuers found the bodies of five missing miners at Xingya Coal Mine at Urad front banner, Bayannur city after an eight-hour search, said a spokesman of the local government. Four people were killed on the spot when a blast rocked the mine at about 3:20 a.m. Monday.

The 16 miners, including four severely injured, are being treated at a local hospital, the spokesman said.

The mine, with maximum output of 300,000 tons of coal a year, is licensed. The cause of the accident is being investigated, he added.

China's mining sector saw 185 accidents in the first quarter of the year, that led to the deaths of 289 people, the State Administration of Work Safety said last Friday. Altogether 1,973 miners were killed in colliery accidents last year.

Poor safety regulations and a lack of safety awareness are usually blamed for the frequent occurrence of colliery accidents.

Inner Mongolia holds China's largest coal reserves. It surpassed neighboring Shanxi Province to become the largest coal producing region in 2010. Its coal output reached 908 million tonnes in the first 11 months last year, rising 26.6 percent from a year earlier, according to latest available statistics.