Two dead, 20 hurt in Turkey mine blast

At least two people died on Friday and 20 were injured when a blast tore through a coalmine in northern Turkey, a top official said, as rescuers tried to reach dozens trapped underground.

The first official toll released by Health Minister Fahrettin Koca could substantially rise, with the local governor saying nearly 50 miners were believed to be blocked hundreds of metres below ground, and the rescue being complicated by nightfall.

The miners are believed to be trapped hundreds of metres below ground after a methane gas blast tore through a pit along the Black Sea coast of Turkey.

Television images showed hundreds of people -- some with tears in their eyes -- congregating around a damaged white building near the entrance to the pit in the Black Sea town of Amasra.

Turkish President Recep Tayyip Erdogan immediately dispatched his interior and energy ministers to the scene to oversee the rescue effort.

Local governor Nurtac Arslan said five people were trapped 350 metres (385 feet) below ground and 44 at another location 300 metres below ground.

She said 14 miners had managed to crawl out of the damaged pit on their own and were now receiving medical assistance.

"Our rescue efforts continue," Arslan told reporters.

Turkey's Maden Is mining workers' union attributed the blast to a build-up of methane gas.

But other officials said it was premature to draw definitive conclusions over the cause of the accident.

The blast occurred moments before sunset and the rescue effort was being impeded by the dark.

Most initial information about those trapped inside was coming from workers who had managed to climb out relatively unharmed.

The local public prosecutor's office said it was treating the incident as an accident and launching a formal investigation.