A TV image shows damage to the Sayano-Shushinskaya power station in southern Siberia after an explosion Monday. (Rossiya TV Channel/Associated Press)

The death toll after an explosion at a Russian hydroelectric power plant has reached 47, with officials warning that the 28 people still missing are likely dead.

Several bodies were discovered overnight in the destroyed turbine room of the Sayano-Shushenskaya power station in southern Siberia, the Emergency Situations Ministry said Friday.

A powerful explosion on Monday had blown out walls and caused the turbine room to flood.

Prime Minister Vladimir Putin visited the site of the accident on Friday and urged RusHydro, the owner of the plant, to compensate the families of the dead and missing equally.

"We can see what's happened — let's not pretend," Putin said.

Russian Prime Minister Vladimir Putin observes the debris at the damaged Sayano-Shushenskaya hydroelectric power station on Friday. (Alexei Druzhinin/Reuters)Putin promised to match the company's payouts with federal money to help families affected by this "huge tragedy."

RusHydro has already pledged to pay one million rubles ($34,000 Cdn) to the families of those confirmed dead.

More than 1,000 workers are still searching the plant for the missing but after four days in near-freezing waters, none are expected to be found alive.

The cause of the accident is unclear but officials cite a faulty turbine and a rise of pressure in the pipes as possible triggers.

A Chechen rebel group claimed responsibility for the accident on Friday, saying that it had sabotaged the plant by placing an explosive in the turbine room. But federal investigators quickly ruled out the claim as a possible cause, issuing a statement that no traces of explosives had been found.

The Sayano-Shushenskaya, which was built in 1978, is Russia's largest power plant and supplies about 10 per cent of Siberia's energy needs.

With files from The Associated Press