His wife, Yelena Baturina, the world’s third richest woman, is appealing a court ruling that statements by opposition figure, Boris Nemstov, were not libelous.

Baturina, the world's third richest woman and her construction company Inteko took Solidarity leader Nemtsov to court in October 2009 over allegations that her husband had used his position to further her business interests.

However, only two of the statements published by Solidarity were recognized as libelous by Moscow arbitration courts earlier this year. Nemtsov was ordered to pay 60,000 rubles ($2,000) in compensation.

Several Kremlin-backed TV channels ran documentaries last week accusing Luzhkov, a bee enthusiast, of holidaying during Moscow's smog crisis this summer and of spending more money on bees than on the capital's smog-hit residents.

They berated him for destroying Moscow's architectural heritage and for using his position to help his wife's amass her estimated $2.9 billion riches.

Commentators say the media war against Luzhkov, by far the most serious in-fighting within Russia's elite since Dmitry Medvedev's 2007 presidential campaign, reflects growing tensions inside the Kremlin ahead of the 2012 presidential elections.

The mayor is allegedly at odds with President Dmitry Medvedev. Their conflict is thought to have its roots in a September article by Luzhkov in the Rossiiskaya Gazeta government daily that hinted at criticism of the Medvedev-Putin tandem.

A government official told the Vedomosti daily that a list of possible successors had already been created for the Moscow mayor’s job including Emergencies Minister Sergei Shoiugu.

Shoiugu's popularity would mean he would be able to deliver the Moscow vote for United Russia just as effectively as Luzhkov, said the newspaper.

Political expert Evgeny Minchenko told the paper that it would be a serious blow to Medvedev's reputation if Luzhkov remains in office. He also said that Prime Minister Vladimir Putin, a perceived Luzhkov ally, had no interest in making a show of public support for the beleaguered mayor as this could lead to more speculation that the premier is the real ruler of the country if the mayor subsequently manages to survive the current standoff.

Ultimately, however, it is allegations of sleaze that have made Luzhkov's mayoral position untenable. Municipal corruption is not unusual in Russia: indeed, according to opposition leader Vladimir Ryzhkov, it is an essential part of Putin's "power vertical". But since 2000, when Putin's arrival in the Kremlin dashed Luzhkov's presidential ambitions, corruption in the capital has flourished, Ryzhkov says.

A senior Kremlin source told Interfax that Luzhkov’s fate was not entirely in his own hands.

“According to Russian law the question of the mayor remaining in office is not decided by Luzhkov,” the source said. “It is the prerogative of the president of the Russian Federation.

The tussle between the Kremlin the mayor escalated today after Yuri Luzhkov dismissed TV allegations against him as "dirt" and said he had no intention of resigning.

In the most significant feud within Russia's ruling elite since 2007, Luzhkov rejected accusations of corruption from Russia's federal TV channels.

A documentary screened last Friday accused him of fleeing Moscow during August's forest fires, and spending more money on bees than on the smog-affected citizens of the Russian capital.

Speaking to supporters in Moscow, Luzhkov said only "an idiot" would care more about bees than sick patients. He also hinted that Vladimir Putin, the prime minister, understood his decision to go on holiday to Austria as smog engulfed the capital. Only "shadowy figures" from inside the presidential administration had objected, he said.

The liberal radio station Echo Moskvy described Luzhkov's comments as a "declaration of war" against the Kremlin. Russian Newsweek, citing Kremlin sources, said the NTV channel was planning another anti-Luzhkov broadcast.

The in-fighting among Russia's clan-based elite is the most serious since autumn 2007, and the months leading up to Putin's announcement that he was endorsing Medvedev – then first deputy prime minister – as his successor. The row blew up after Luzhkov criticised the Kremlin last week, questioning Medvedev's decision to suspend a Moscow-St Petersburg road-building project.

The feud divides the ruling United Russia party.

United Russia deputies in the Luzhkov-run Moscow city government passed a motion supporting their embattled mayor. Putin has so far been silent. But it is hard to imagine the unprecedented Kremlin campaign against Luzhkov could have taken place without his approval.

Speaking earlier this week, the liberal opposition leader, Boris Nemtsov, said Medvedev faced a choice: sack Luzhkov over the next few days or become "an all-Russian laughing stock".

The liberal radio station Echo Moskvy described Luzhkov's comments as a "declaration of war"

Prices of Eurobonds issued by Bank of Moscow fell to their lowest in almost two months on Wednesday, on speculation about the possible departure of the capital's powerful, long-serving mayor.

The bank, a top-10 Russian lender, is controlled by Moscow's government. Its 2015 bond traded at 104.35, its lowest since late July, taking losses in the past week to around 4 percent and underperforming a broadly stable market.

"The Bank of Moscow bonds have come under fire due to rumours over the possible departure of Moscow mayor Yuri Luzhkov," Olga Sterina, analyst at Unicredit, said in a note.