At least six Indian sailors were killed and as many were missing after two fuel ships carrying Indian and Turkish crew members caught fire in the Kerch Strait on Monday, the Ministry of External Affairs said on Wednesday. Four Indian soldiers were rescued, the ministry added.

Russian Maritime Agency, along with other Russian agencies, has resumed a search operation for the missing sailors, PTI reported.

One of the ships, the Candy, had 17 members on board, and the other ship, Maestro, had 15 members. Both ships were flying Tanzanian flags. One of them was a liquefied natural gas carrier and the other a tanker. Preliminary information suggested that the fire broke out when fuel was being transferred from one vessel to the other.

The Kerch Strait is of strategic importance for both Russia and Ukraine. It is an important lifeline for Ukraine that allows ships leaving the port city of Mariupol to access the Black Sea. For Russia, it is the closest point of access to Crimea, which it annexed in 2014.

“Arrangements are being made after completion of necessary formalities to bring back the bodies of the deceased to India,” the MEA said in a statement. “The repatriation of the other sailors is also being facilitated through Director General Communication Center, Indian Registry of Shipping, Mumbai.”

A senior official of the Directorate General of Shipping had earlier said that dozens of vessels were looking for survivors in the vicinity of the accident site. The official said the wreckage was scattered. “Some of our sailors have contacted their families back home about making it, while a few have been rescued after they jumped out of the blazing ships,” the official said.

The official said the directorate was in contact with the Foreign Ministry in Delhi, which is coordinating with the embassy in Moscow, while the Maritime Rescue Coordination Centre was in touch with its Russian counterparts.