The latest demand followed a federal audit and brought the amount the tax authorities say is owed in 2001 to 935 million dollars. The Moscow stock market's RTS index fell more than three percent on the news, which coincided with the announcement in Moscow of an April 27 verdict in the trial of tycoon Mikhail Khodorkovsky, whose Yukos company has been crippled by a 27 billion dollar demand for back taxes. The development came as major Russian investment showcases took place in Britain and in Germany, where President Vladimir Putin was meeting German Chancellor Gerhard Schroeder. TNK-BP had previously received a revised 2001 tax bill for four billion rubles (144 million dollars) for the same period, a claim it has contested in court. But a spokesman for TNK-BP said "we have received a new tax claim for 22 billion rubles," or around 791 million dollars, for 2001." The spokesman, who asked not to be named, said the new tax claim followed an audit by federal tax authorities, while the previous bill was for value-added and profit taxes and was issued by regional tax officials. The spokesman declined to say whether TNK-BP would challenge the latest tax claim. Putin promised business leaders last month to introduce tighter regulations on tax controls, which many businesses complain are increasingly used as an instrument for the government to pressure companies. However, some investors still feel nervous. "It's not a new Yukos affair, but it is clearly bad news at a time when the Russian authorities are trying to improve the image of Russia and attract investments," Valery Nesterov, an analyst for Troika Dialog investment company said. Chris Weafer, a strategist for Alfa Bank whose parent company owns half of TNK-BP said the news had "spooked the market." Weafer said TNK should not be overly surprised by the demand itself but that the timing made some fear"yet another example of a serious split at the top of the government, the lack of a clearly-stated strategy by the president, or poor control over the actions of the state bureaucracy." PIN//AFP