Officials said Wednesday an explosion at a coal mine in the rebel-held Donetsk has killed more than 30 people and injured 14. A rescue team was working to remove the poisonous gas before entering the Zasyadko mine, according to local mining safety service chief Vladimir Tsymbalenko. Local officials estimate 70 people were working in the mine when the blast occurred. The cause of the explosion was not immediately clear. An explosion at Zasyadko killed 106 people in 2007.