At least 30 miners have been killed and a further 17 injured in a gas explosion in a coal mine in the northern Iranian city of Tabas, state broadcaster IRIB reported on Sunday, citing local authorities. Some of the injured were in critical condition, and there were fears that the death toll could rise. Seventy miners were in the mine at the time of the blast, which took place overnight, the report said. Rescue work was proceeding only slowly on account of thick smoke, IRIB reported. Hopes for survivors still trapped in the mine were said to be fading.