Russia's Rosneft vowed to push ahead with a strategic alliance with BP , despite a block on the deal by the British oil company's partners in joint venture TNK-BP .

Rosneft Chairman Igor Sechin said an arbitration panel ruling preventing BP and the state-controlled energy giant from jointly exploring Russia's Arctic region and from executing a $16 billion share swap did not void the deal.

The court didn't block (the deal), it extended the injunction until April 7. We must await the court's verdict, Sechin, also Deputy Prime Minister, told reporters on Friday.

Sechin argued Rosneft had suffered losses as a result of the actions by BP's TNK-BP partners Access-Renova (AAR), which pursued court action against the BP-Rosneft tie-up, arguing the alliance violated their right of refusal.

He said Russia's largest oil company was satisfied with BP as its partner and would defend its interests.

However, Stan Polovets, AAR's chief executive officer, told Reuters that although BP had requested another tribunal hearing on April 4 to argue that it should be allowed to swap its shares with Rosneft without carrying out any joint projects together, this would not alter the situation.

This is not a temporary injunction with a predetermined 'expiration date'. We don't expect anything to change in the foreseeable future, not on April 4, not on December 4, he said.

AAR, which represents BP's billionaire partners in TNK-BP, had hailed Thursday's arbitration ruling as a victory in their bid to prevent BP hooking up with Rosneft.

AAR said BP was now prohibited from entering into any future share arrangement with Rosneft that has any kind of strategic component, potentially opening the door for a rival to step in and replace BP as Rosneft's partner.

The ruling also raised immediate questions about BP Chief Executive Bob Dudley's tactics in Russia and raised the prospect Rosneft could look elsewhere for the expertise it needs to get oil out of Russia's Arctic region.

Given his (Dudley's) past relationship in Russia, how difficult it has been, he should have been a bit more appreciative of how tricky it can be operating in Russia, Arbuthnot Securities analyst Dougie Youngson said.

Rosneft head Eduard Khudaynatov said in January the group was awash with proposals from foreign companies for exploring in the Arctic, and Royal Dutch Shell , BP's arch rival, has already confirmed its interest.

The cleanest thing for Rosneft, if it wants to start developing its offshore acreage and resource potential, is to choose a different partner, Sanford C. Bernstein analyst Oswald Clint said, adding TNK-BP lacked the necessary know-how.

TNK-BP shareholders said earlier this month the joint venture could supplant BP in the share swap with Rosneft.

This was rejected by Rosneft, which recently struck deals with U.S. oil majors Chevron and Exxon Mobil to explore in the Black Sea.

BP shares closed 0.6 percent higher, with analysts saying many had not priced the Rosneft deal into estimates because of uncertainty from the start. Rosneft closed 1.2 percent lower.

NOT STRAIGHTFORWARD

BP's embarrassment over the ruling was compounded by the fact that chief executive Dudley had been seen as more plugged into the complexities of Russian oil than most.

He was in charge of TNK-BP before being forced to leave Russia in 2008 due to what he said was a campaign of harassment by the joint venture's co-owners.

As well as bad news for Dudley, who took over as CEO last year following BP's disastrous Gulf of Mexico oil spill, Thursday's decision was seen as a blow to the Russian government, which has struck several deals with energy majors to tap new oil and gas regions to sustain long-term output.

Dudley played down the impact in an internal memo, saying: BP's long history in Russia demonstrates progress and growth is not always straightforward. But it has consistently been successful over the long term.

Dudley said BP would seek a ruling on whether the share swap under which it would exchange 5 percent of its own stock for a 10 percent holding in Rosneft -- may proceed on its own.

I guess they (BP) feel that over time, that (the share swap) would allow them potentially opportunities at some stage, but obviously it's a sub-optimal solution relative to the original plan, said Barclays Capital analyst Lucy Haskins.

Few expect a quick resolution to the stand-off.

This was always going to be a tricky situation trying to balance a relationship with Rosneft and TNK. So, I think this is going to run for much longer than BP has been letting on, Youngson at Arbuthnot Securities said.

(Additional reporting by Douglas Busvine, Melissa Akin and Vladimir Soldatkin in MOSCOW and Stephen Jewkes in MILAN; Writing by Alexander Smith; Editing by Dan Lalor and Sophie Walker)