The "Kolskaya" oil drilling rig in the Kola Bay near Russia's northern seaport of Murmansk

Rescuers have spotted a life raft which may contain survivors from a Russian oil rig disaster feared to have claimed dozens of lives.

Jack-up oil rig, the Kolskaya, capsized on Sunday while being towed around 120 miles of the coast of Sakhalin Island during a storm.

At least seven people are confirmed dead while 46 remain missing in the icy waters. A group of 14 men were rescued in the moments immediately following the disaster.

Despite rescuers claiming that chances of survival were "negligible", a life raft carrying at least 15 people has been spotted. It is not known whether the men are dead or alive.

President Dmitry Medvedev has ordered an investigation into the cause of the disaster, which could be the deadliest offshore oil accident in Russia's history. It is feared that safety violations could have caused the accident.

"The investigation is looking into safety regulation violations during the towing of the platform and a disregard of poor weather conditions as the main reasons for the incident, as there was a strong storm in the area" the investigative committee said.

"This is a horrible tragedy, which caught the crew off-guard," said Dmitry Dmitriyenko, governor of the norther Murmansk region, where 33 of the crew live.

"I am asking you to believe in the rescue of the crew members, there is still a chance."