Rescuers have abandned attempts to douse the flames of two burning liquified gas carrying ships in the Black Sea near Crimea’s Kerch Strait. The vessels will be left to burn out.

Russian state-run news agency TASS reports local rescue authorities as saying 10 crew are confirmed dead, with a further 10 not accounted for.

Russian rescue authorities say the two ships were alongside each other transferring fuel when the fire started. The flames quickly spread to both ships, setting off an explosions aboard both of them.

The ships involved were the Kandy, with a crew of 17, and the Maestro, with 14 on board.

AFP reports “no signal from either one of the two captains” had been received.

Reports state 11 people have so far been rescued.

“The search and rescue operation continues,” the Maritime Rescue co-ordination Center said in a statement. “There is a threat of a gas explosion,

Russian news service TASS reports rescuers as saying the two Tanzania registered ships were ‘illegally anchored’. A criminal investigation has been launched into the deaths.

The incident has occurred in neutral waters outside the contested Kerch Strait, linking the Sea of Azov with the Black Sea. Russia has moved to seize the international waterway following its annexation of the adjoining Crimea Peninsula in 2014.