BP HAS recalled 148 foreign employees on secondment to its Russian joint venture TNK-BP because of visa problems, as pressure on the UK's biggest investment in Russia intensified.

The 148 technical staff, mostly British and Americans, have been told to stay away from work until confusion about Russia's new visa arrangements for foreign workers has been resolved.

Most are still in the country. TNK-BP said they were being recalled as a precaution. "There is some cloudiness and greyness about the status of their visas," after changes to migration laws late last year, it said.

The interior ministry said it had opened a criminal case into large-scale tax evasion by Sidanco, an oil unit that once formed the company but was dissolved, for about $42 million.

Tension over TNK-BP, 50 per cent owned by BP and 50 per cent by three Russian tycoons, has escalated in recent days. Police last week raided BP and TNK-BP offices, while the Russian security services said they had charged an employee of TNK-BP and his brother for industrial espionage.

A source said TNK-BP had been investigated by the security services, suffered visa problems and faced the environmental agency probe. "Chaos or conspiracy: you decide," he said.

Some think TNK-BP is identified for takeover by Gazprom, the state-controlled gas company. Gazprom has said it hoped to complete a deal to take over TNK-BP's biggest gas project by the end of April. TNK-BP was forced to sell its 62.9 per cent stake in the field to Gazprom last year, but the deal has been repeatedly delayed.

There is speculation Gazprom also seeks to buy out the Russian half of TNK-BP. The Russian shareholders have denied they want to sell.

BP's stake in TNK-BP is important, at 22 per cent of last year's production and 19 per cent of its oil and gas reserves. - (Financial Times service)