More than 20 people are reported missing following a gas explosion Tuesday in a coal mine in eastern China, according to the Xinhua news agency. Rescuers have rushed to the location but exact casualty estimates were not yet available, the report added.

According to a report from Associated Press, which cited China Central Television, 29 workers are trapped underground after the explosion while 10 others managed to escape, and one of them was injured. Thirty rescuers are at the scene waiting for rescue equipment, the report added. The accident took place at about 5:00 a.m. local time (5:00 p.m. EDT), Xinhua reported, in Huainan City in Anhui province, about 292 miles from Shanghai. 

The accident at the mine, which had reportedly been ordered twice to close down in June, yet again highlights the lax safety measures in China's accident-prone mines. 

In June, a blast in a coal mine in the southwestern city of Chongqing killed nearly 22 people. In May, a pipeline collapsed in a coal mine in northwestern China’s Shaanxi district, killing at least 11 people. In 2012, another blast in a mine in southwestern China killed 19 people.

According to government estimates, more than 100 people have been killed in mine accidents in the country since the beginning of the year.