A huge sinkhole in China swallowed a bus and several pedestrians Monday evening, killing at least six people and leaving 10 missing. Video footage from Chinese state media appears to show people at a bus stop in Xining, the capital of Qinghai province, running from the sinking ground. A few seconds later, a large explosion causes flames to burst from the sinkhole, according to video of the incident. It’s unclear how many people were on the bus at the time of the incident. Agence France-Presse reports that in addition to the bus, several people fell into the hole, and that 16 people were taken to a local hospital. Rescue teams were on the scene and the cause of the accident is under investigation, according to Chinese state media.