Yukos insists the Sibneft merger is still on

After a board meeting in London, Yukos said the merger was "still fully in place", despite Sibneft shareholders trying to torpedo the $11bn deal.

The group added its estranged merger partner had not provided an acceptable divorce proposal.

In order to push the deal through, it has now called an extraordinary general meeting to replace the Sibneft board.

Putting some friendly faces on Sibneft's board could be the way for Yukos to ensure the merger goes ahead.

Yukos technically owns 92% of the smaller partner since the deal was partially completed last year.

Control battle

The Sibneft shake-up is an attempt by the embattled oil firm to regain the initiative in what has become a bitter and highly politicised corporate fight involving two of Russia's biggest firms.

After the meeting, Yukos said: "The board ... will not tolerate direct interference by any core shareholder in the functioning of the company."

The statement was a reference to a group led by Roman Abramovich, Chelsea Football Club's owner.

Mr Abramovich is a core Sibneft shareholder who now holds a significant stake in Yukos.

According to Yukos officials, he has been trying to wrest control of the company's management.

But despite its brave words, the oil company is severely weakened.

Problems mount

Former Yukos boss Mikhail Khodorkovsky remains in jail

Its boss and top shareholder, Mikhail Khodorkovsky, has been in jail since 2003 on tax fraud charges and the firm also faces a tax underpayment charge of $3bn.

Russian authorities also issued international arrest warrants for a further 10 Yukos names on charges of fraud and other offences earlier this week.

Meanwhile, reports suggest that companies affiliated to the Sibneft camp filed a legal challenge to the deal that could nullify part of the merger agreement.

Critics of President Vladimir Putin have said the Russian leader is trying to keep Mr Khodorkovsky out of politics.