A gas leak killed 25 miners and 20 others remained trapped underground Saturday at a coal mine in China's southwestern city of Chongqing, the official Xinhua News Agency said. Rescuers are working to release those trapped, the news agency said. The cause of the accident is still being investigated. There were 131 people working in the Tonghua mine when the accident happened at 11 a.m. (0300GMT), but 86 escaped safely, the report said.