Search and rescue teams seeking survivors after an oil rig capsized in icy seas off Russia are said to have spotted a life raft with people on board.

Fourteen workers have already been rescued after Sunday’s disaster. The rig’s owner says it is not clear whether those on the life raft were alive. But the reports, raising fresh hopes after the rig sank off the far-eastern island of Sakhalin, have been disputed by Russian government officials.

A total of 67 crew were on board when the drilling rig went down while being towed through a winter storm. The bodies of 16 of them have been found.

Investigators are looking into whether safety regulations were violated during the towing operation and at the role poor weather conditions may have played.