UPDATE 3-Russian tycoon Usmanov bids for Norilsk - co-owner

(Adds source on Usmanov bid)

By Aleksandras Budrys

MOSCOW, Feb 19 (Reuters) - Russian billionaire Alisher Usmanov has made a bid to merge his assets with Norilsk Nickel (GMKN.MM)(NKELyq.L), which could complicate plans by RUSAL to gain control of the huge Russian metals company.

Norilsk has received a merger proposal from Usmanov, a spokeswoman for Interros, the investment vehicle of billionaire Vladimir Potanin that owns a blocking stake in Norilsk, told Reuters on Tuesday.

"We have received a proposal and Norilsk's board has charged the management to investigate such a possibility," the spokeswoman said.

This was the latest move in a struggle by some of Russia's richest men for control of the world's top nickel and palladium producer after long-term business duo -- Potanin and Mikhail Prokhorov -- decided to split their various assets.

Potanin, whose Interros owns a blocking stake of more than 25 percent plus one share in the metals company, is eager to avoid the sale by former partner Prokhorov of a blocking stake in Norilsk to United Company RUSAL, one of the biggest aluminium producers in the world.

A spokesman for RUSAL, which is controlled by metals magnate Oleg Deripaska, declined to comment, as did a spokesman for Usmanov's Gazmetall.

"I have heard nothing about this move," a source close to the Kremlin told Reuters on condition of anonymity. "Potanin and Prokhorov's split is going according to the previous scheme, but it is unclear how it will all end."

"For Potanin this could be a type of defence because with two strong shareholders (Usmanov and Deripaska), no-one would have a majority and then the management would have a deciding role and minority shareholders could have more say than even the main shareholders," the source said.

If Usmanov's action gets serious backing, and if he can secure the financing, then it would lock two of Russia's best connected businessmen into a battle for Norilsk, which has a market capitalisation of $55 billion.

Gazmetall, a Russian iron ore and steel company, controls Russia's two largest iron ore mines, Lebedinsky GOK and Mikhailovsky GOK, as well as steel makers Urals Steel and Oskol Electrometallurgical Plant.

A source close to the situation who requested anonymity said Dresdner Kleinwort Bank had advised Gazmetall that it would be rational for it to merge with Norilsk.

Norilsk, which controls one of the world's richest mining deposits, was founded under Soviet dictator Josef Stalin and remained a state company until the Soviet Union collapsed.

In the 1990s, it was privatised and a controlling voting stake was sold off in a shares-for-loans scheme in which a small group of well-connected tycoons gained control over some of the Soviet Union's most attractive resource companies. (Additional reporting by Anastasia Onegina, Robin Paxtona and Anatasia Teterevleva) (Writing by Guy Faulconbridge, Editing by Richard Chang, Toni Reinhold)