Dozens are trapped hundreds of metres below ground after an unexplained blast tore through a mine in northern Turkey.

Television images showed hundreds of people, some with tears in their eyes, congregating on Friday 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 told reporters that five people were trapped 350 metres (1,150 feet) below ground and another 44 at another location 300 metres (984 feet) below ground.

Amasra’s mayor, Recai Cakir, told HaberTurk television channel that there were 87 workers inside the mine at the time of the blast.

At least 14 were either rescued or came out of the mine on their own, Cakir said. Two of them were injured.

According to information received, at least six of the workers were lying “motionless” inside the mine, the mayor stated, but said he did not know if they were dead or injured.

A malfunction at the mine’s power distribution unit caused the explosion, disaster authority AFAD said.

Earlier, 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 conclusions about the cause of the accident.

In Turkey’s worst mine disaster, a total of 301 people died in 2014 in a fire inside a coal mine in the town of Soma, in western Turkey.