At least 22 people have died after an apparent methane blast tore through a pit on Turkey’s Black Sea coast, with rescuers searching for dozens of coalminers still trapped hundreds of metres underground. Süleyman Soylu, the interior minister, said 28 people who either managed to crawl out on their own or were saved by rescuers had suffered various injuries in one of Turkey’s deadliest industrial accidents in years. “We are facing a truly regretful situation,” Soylu told reporters after urgently flying out to the small coalmining town of Amasra. “In all, 110 of our brothers were working [underground]. Some of them came out on their own, and some of them were rescued.” He also confirmed early reports that almost 50 miners were still trapped in two separate areas between 300 and 350 metres below ground. Television images showed anxious crowds congregating around a damaged white building near the entrance to the pit in search of news about their friends and loved ones. Recep Tayyip Erdoğan, the Turkish president, was expected to fly to the scene of the accident on Saturday. Most initial information about those trapped inside was coming from workers who had managed to climb out relatively unharmed. The Amasra mayor, Recai Çakir, said many of those who survived suffered “serious injuries”. The blast occurred moments before sunset and the rescue effort was being impeded by the dark. Turkey’s Maden-İş mining workers’ union attributed the blast to a buildup of methane gas. But other officials said it was premature to draw definitive conclusions over the cause of the accident. Rescuers sent in reinforcements from surrounding villages to help search for signs of life. Television images showed paramedics giving oxygen to the miners who had climbed out and then rushing them to the nearest hospitals. The local governor said a team of more than 70 rescuers had managed to reach a point in the pit about 250 metres below. It was not immediately clear if the rescuers would be able to come any closer to the trapped workers or what was blocking their further passage. Turkey’s AFAD disaster management service said the initial spark that caused the blast appeared to have come from a malfunctioning transformer. It later withdrew the report and said the methane gas ignited “unknown reasons”. The local public prosecutor’s office said it was treating the incident as an accident and launching a formal investigation. Turkey suffered its deadliest coal mining disaster when 301 workers died in a blast in the western Turkish town of Soma in 2014.