Oil giant BP has been forced to recall the head of its Russian joint venture TNK-BP, Robert Dudley, after a dispute left him without a work permit.
Although Mr Dudley will continue in his role as chief executive of the 50-50 oil exploration joint venture, he has left the country "temporarily" as a row between BP and its Russian partners escalated.
BP said he will continue to run the company from outside the country and the business will trade as normal.
Mr Dudley said: "I shall seek to provide continuity of management in the best interests of all shareholders pending a resolution of the differences between Alfa, Access, Renova and BP.
"I will endeavour to continue to serve the best interests of all shareholders and hope that administrative pressure on the group will now ease.
"I hope this will enable our employees to continue with our business, outside of the media glare whilst the shareholders seek to resolve their differences."
BP believes the investors who operate Alfa, Access and Renova (AAR), which owns half the business, have orchestrated a campaign to gain control of TNK-BP after rumours of a buy-out surfaced.
Relations between the two sides soured when BP employees were refused visas by the Russian authorities.
BP has accused the Russians of 'corporate raiding tactics' while AAR claims BP is running the business for its own gain, rather than in the interests of all shareholders.
On Tuesday, BP withdrew all of its geologists and engineers involved in the TNK-BP venture from Russia.
In a shareholder presentation for the first half, TNK-BP said 140 BP employees have left the company.
Although on track for record results in 2008, "shareholder issues may impact performance during 2009" the company said.