An oil drilling rig with 67 crew members on board capsized and sank on Sunday in icy waters off the Russian island of Sakhalin.
Forty nine crew members are still missing. Four were found dead. Fourteen survivors were rescued by nearby boats.
The rig was being towed to port when it encountered a storm. Officials believe crashing waves washed away rescue rafts before crew members could get them into the water.
A company spokesman said the rig poses no ecological danger.
But the incident could deal a blow to Russia's efforts to expand offshore oil and gas exploration. Russia is the world's largest energy producer.
Katharine Jackson, Reuters.