UPDATE 1-Telenor seals Vimpelcom stake buy despite Russian opposition

* Telenor lifts stake to 43 pct through option deal

* Calls on Altimo to jointly buy Pinchuk's stake

(Adds Telenor spokesman, background)

OSLO, Oct 1 (Reuters) - Norway's Telenor has completed its purchase of an increased stake in Russia's Vimpelcom in the face of opposition from co-shareholder Altimo and Russia's anti-monopoly watchdog FAS.

The purchase of the 3.5 percent stake from Egyptian tycoon Naguib Sawiris, which raises Telenor's stake to 43 percent, is the latest episode in a long-running campaign by Telenor to secure what it regards as an equal holding in the Russian company alongside locally-based Altimo.

Telenor had said on Aug. 17 it would buy the stake after Sawiris exercised his option to sell.

But the deal helped spark a fresh outbreak of hostilities between the two sides, who are battling for control of Vimpelcom, which has a market value of $16 billion and has a strategic position because it holds a quarter of Russia's mobile market.

Telenor's stake would eclipse Altimo's 40.5 percent holding, but the Norwegians argue that a further 6 percent stake owned by

Bertofan, an investment vehicle of Ukrainian tycoon Viktor Pinchuk, should in reality be counted as "parked" shares actually owned by Altimo and which should be counted as part of the latter's total stake.

Telenor says the two main owners should divide up the Bertofan shares to restore ownership parity.

"We now sit with almost 43 percent, and they (Altimo) have a controlling share together with Bertofan of 46 percent. We suggest that we split that 6 percent share in a way that makes us equal in terms of voting power," Telenor spokesman Dag Melgaard told Reuters.

FAS previously filed a lawsuit against Telenor and called on the Norwegian group to sell part of its 43 percent stake to achieve what it regards as parity.

"We will keep these shares," Melgaard said, adding that Telenor had not been in contact with Altimo ahead of Monday's announcement. "Our proposition is to maintain equality between the two biggest shareholders on the board."

The head of FAS said in a statement the Norwegian company's action had gone against an injunction by a Russian court.

"I regret this, because an injunction by a Russian court has been violated," Igor Artemyev said in comments issued by the service's press office. "Unfortunately we cannot add anything for now."

(Reporting by Victoria Klesty and Joachim Dagenborg; Additional reporting by Maria Kiselyova in Moscow; Editing by David Holmes)

((victoria.klesty@thomsonreuters.com)(+47 2293 6979)(Reuters Messaging: victoria.klesty.thomsonreuters.com@reuters.net))