At least four people are dead and 49 others missing and presumed dead after a Russian oil rig capsized and sank early Sunday in the frigid Sea of Okhotsk.

The Russian Transportation Ministry said 14 crew were rescued by an icebreaker and a tug boat after the platform was smashed by a giant wave and began sinking while under tow 200 kilometers off Sakhalin island. The ministry said the wave broke portholes and ripped empty lifeboats from their moorings. Water temperatures were reported at 1 degree Celsius, severely diminishing prospects for further rescues hours after the tragedy.

Russian President Dmitry Medvedev ordered a probe of the disaster.

Authorities say the giant rig was headed from the Kamchatka peninsula to Sakhalin when it capsized.