EXCLUSIVE-UPDATE 1-BP's Russian arm in Siberian court blow

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By Michael Stott and Dmitry Zhdannikov

MOSCOW, May 13 (Reuters) - BP's (BP.L: Quote, Profile, Research) Russian venture TNK-BP said on Tuesday court action by a local brokerage had stopped it using key specialist staff, the latest problem to hit the company as a struggle rages over its ownership.

Since the struggle began last year, TNK-BP, which has revenue of $40 billion, has been raided by Russia's security service, had an employee arrested for alleged espionage, had secondees' visas declared invalid and been hit with a tax claim.

In the latest twist, a TNK-BP spokesman said Tetlis, a small Moscow brokerage, had claimed in a Siberian court that TNK-BP's service agreement governing the use of BP (BP.L: Quote, Profile, Research) specialists was improper. Tetlis alleged it constituted a special dividend to one shareholder and disadvantaged others, he added.

The Tyumen arbitration court issued an injunction to TNK-BP to halt activities under that agreement and stop making payments. It will hear the Tetlis claim on May 20.

"Both the claim and the injunction we don't believe have any solid legal basis and we will be continuing to pursue our legal options," the TNK-BP spokesman said.

BP and a group of Russian billionaires share 50/50 control of unlisted TNK-BP, which in turn owns 95 percent of listed TNK-BP with a 5 percent free float. Efforts by the state to gain a controlling stake have upset this delicate balance.

As a result of the injunction, all 148 BP secondees -- including well selection and field development experts -- had been barred from working at TNK-BP, Russia's second biggest private oil company, since May 5, the company said.