MOSCOW, July 3 (Xinhuanet) -- Russian law enforcement officials are attempting to enter the embattled oil giant Yukos headquarters in Moscow, the Interfax news agency reported Saturday, citing a Yukos source as saying.

    "Since it's a weekend, there aren't any people from the company's management or its lawyers in the office now, and therefore it is impossible to find out which security agency's representatives have come to our office. It is also unclear whether they have the proper documents," the source said.

    Interfax said that about 100 law enforcement officers had been attempting to enter the Yukos headquarters for about an hour and a half.

    The law enforcers told Interfax that there were Prosecutor General's Office and Interior Ministry officials among them. They said they didn't know exactly what the purpose of their presence there was, and some of them assumed that they might be tasked with inventorying Yukos's assets.

    The move came as a series of actions by the law enforcement agencies against Yukos, the nation's biggest oil exporter, in recent days following a court ruling requiring Yukos to pay a 3.4 billion US dollars in back taxes for 2000 which came into force onJune 29.

    The Russian Tax Ministry accuses Yukos of evading taxes by channelling funds through offshore companies. On April 14, the ministry completed an audit of Yukos tax payments in 2000 and subsequently hit the company with a 3.4 billion dollar tax demand.

    Yukos has said the demand would bankrupt it as the company's assets have been frozen by the earlier court ruling and Yukos would thus be unable to raise enough cash in time to pay the taxesdemanded by the ministry.

    On Thursday, court bailiffs presented Yukos with an execution order on the back taxes claim and gave Yukos five days to pay the tax bill. Later on the same day, all the Yukos accounts in Russianbanks were frozen.

    Also on Thursday, the tax ministry issued another tax claim against Yukos for the year 2001, demanding it pay 98 billion rubles (3.3 billion dollars) in back taxes.

    On Friday, the Moscow Arbitration Court upheld the freezing of Yukos assets as an enforcement measure on the tax ministry's multi-billion dollar claim against it.

    The nearly one-year judicial campaign against Yukos is seen as a political move to stifle the financial and political clout of its former chief executive Mikhail Khodorkovsky who had reportedlysponsored political opponents against President Vladimir Putin.

    Khodorkovsky has been detained since last October on charges offraud, embezzlement and tax evasion.

    But Putin, who was re-elected to another four-year term in March, has repeatedly denied any political motive behind the Yukoscase, saying it is part of the country's anti-corruption campaign to crack down on economic crimes.

    Putin said earlier last month that the Russian government is not interested in bankrupting the oil giant. Enditem