Natural gas giant Gazprom took control of NTV last week in what the network and its supporters say was a Kremlin-orchestrated assault against critical media.
Gazprom, a major NTV shareholder, claimed that the move was motivated by the need to cut NTV's losses and try to recover debts.
Igor Shabdurasulov, a former presidential aide, did not explain why he decided to leave his position as chairman of the board of directors of TV6, the Interfax news agency reported.
His decision came after TV6 owner Boris Berezovsky, a Russian tycoon in self-imposed foreign exile, agreed to hire NTV journalists including chief editor Yevgeny Kiselyov.
Berezovsky had close ties to former President Boris Yeltsin's inner circle and was once a bitter rival of NTV founder Vladimir Gusinsky, but the two tycoons appear to have found a common foe in Yeltsin's successor, Vladimir Putin.
TV6 executive director Alexander Ponomaryov and board member Ruslan Fomichev were also planning to quit, Shabdurasulov said.
Ponomaryov blamed his departure on internal conflicts at the station, apparently with newcomers from NTV.
"There are all kinds of ethical misunderstandings taking place because some people are saying they are better than others," Ponomaryov was quoted as saying by Interfax.
A newspaper and a weekly magazine affiliated with NTV and noted for the same kind of critical reporting also came under fire this week. The Segodnya newspaper did not appear on newsstands Tuesday, and staffmembers were barred from the editorial offices of Itogi magazine.
Itogi publisher Dmitry Biryukov reiterated that Segodnya was closed because it was losing money.
Germany's Foreign Minister Joschka Fischer expressed concern Wednesday over media freedom in Russia in the wake of the NTV takeover.
"The news of the last few days the takeover of the television channel NTV, the closure of the daily newspaper Sevodnya and the weekly magazine Itogi cause the federal government great concern," Fischer said in a statement.
In a briefing this week, U.S. State Department spokesman Richard Boucher said the U.S. thinks "the overall pressure on NTV, the overall way that this has been handled, certainly has a political motivation, and that its preservation is important for the future of freedom of the press in Russia."
Meanwhile, Gusinsky, the founder of both publications and NTV, won a victory in a Spanish court Wednesday when a three-judge panel turned down a Russian request to extradite him on fraud charges.
Court sources said two of the three judges at the High Court hearing the case had rejected the extradition request, ruling the alleged fraud offenses did not represent a crime in Spain.
"Mr Gusinsky is on oe hand very happy with today's verdict, but he is also very concerned about the situation in Russia," Gusinsky's defense lawyer Domingo Plazas said.
Spanish prosecutors may appeal to another panel at the High Court against the ruling on behalf of Russian authorities within three days, Plazas said.
"We don't think this decision is a disaster, and ways of securing Gusinsky's extradition still exist," Interfax news agency quoted Natalya Vishnyakova, spokeswoman for Russia's Prosecutor General, as saying. "All possibilities have not been exhausted."
Prosecutors in Moscow have accused Gusinsky one of the "oligarchs" who grew rich in Russia's first years of transition !51; of large-scale fraud linked to his Media-Most empire.
Earlier this month, U.S. media magnate Ted Turner announced he had reached a deal to buy into NTV, Media-Most's flagship television station, to maintain NTV's independence. But that deal was believed unlikely to go ahead after Gazprom's takeover.
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