A Russian tycoon who has financed a newspaper critical of the Kremlin and supported the opposition has been charged with hooliganism and assault for punching a fellow billionaire during a television talk show. He dismissed the criminal case as politically motivated.

Russia's top investigative agency, which announced the charges Wednesday, said the defendant, Alexander Lebedev, cannot leave Moscow while the probe is under way. In Russia, filing charges marks the start of a criminal investigation, which may or may not lead to a trial.

The charges refer to a September 2011 incident during which Lebedev punched property developer Sergei Polonsky during a TV show, sending him tumbling to the ground.

Lebedev said in comments carried by the Interfax news agency that he considers the charges against him political and "completely made up."

He could face up to seven years in prison, if he's convicted on hooliganism charges similar to those that were filed against three members of the feminist rock band Pussy Riot. They were sentenced to two years each last month for performing a "punk prayer" against President Vladimir Putin in Moscow's main cathedral.

Putin has taken an increasingly tough course against dissent after massive protests against his rule last winter, with searches and interrogation of opposition activists and the passage of repressive bills.

Made fortune in banking

Lebedev, whose net worth was reported by Forbes magazine to be $1.1 billion US, made his money in the banking industry. He has financed the Novaya Gazeta newspaper, which is fiercely critical of the Kremlin, and the British papers the Independent and the Evening Standard.

Lebedev's son, Yevgeny, who owns the two British publications, tweeted that his father is "being targeted by people who don't like his stance against corruption, and hate Novaya." He later described the charges as "extraordinarily disproportionate."

"My father has been targeted because of his determination to fight against corruption and to be a crusader for democracy in a country where this has not always been welcome," Lebedev's son said in a statement. "I really hope that this does not presage a new phase of crackdowns on those who speak out against injustice."

The tycoon had said last month that he was being forced to sell his assets because of pressure by Russia's Federal Security Service, the main KGB successor agency. He said the pressure was rooted in corruption investigations by Novaya Gazeta, alleging that some of the service's officers were involved in corruption.

Lebedev and former Soviet leader Mikhail Gorbachev own a 49 per cent stake in the newspaper, while the remaining shares are controlled by Novaya's staffers.

Novaya Gazeta's relentless criticism of the Kremlin, and its investigations into official corruption, have put many of its journalists under fire. Four of the paper's reporters have been killed since 2000, including Anna Politkovskaya, a fierce critic of the Kremlin and its policies in Chechnya. She was gunned down in the elevator of her Moscow apartment building in 2006. Others have been harassed and physically attacked.

KGB veteran

Lebedev has also supported Alexei Navalny, a charismatic anti-corruption crusader and blogger who was a key driving force against massive protests last winter against Putin's rule. Lebedev, a KGB veteran like Putin, so far has avoided blaming the president for his woes, pointing the finger at security services for the campaign against him.

Lebedev's lawyer, Genri Reznik, told Interfax that the newly announced charges come as a "punishment for Lebedev's social activities, his fight against corruption, his funding of an opposition newspaper and support for Navalny."

Lebedev owns the National Reserve Bank and has a stake in Russian flag carrier Aeroflot as well as his own Red Wings airline.