The head of the Russian parliament's ethics committee resigned his seat on Wednesday after a leading opposition anti-corruption crusader accused him of having secret property in the United States.
Ruling party lawmaker Vladimir Pekhtin quit after Alexei Navalny, arguably the most charismatic leader of Russia's opposition movement, accused him of owning property in the resort town of Miami Beach in Florida that he had not declared.
The resignation of such a prominent ruling party lawmaker is the biggest scalp yet for Navalny's anti-corruption investigations that have turned the lawyer into a figurehead of the anti-Vladimir Putin protest movement.
Documents that he posted online this month show that Pekhtin, a member of the ruling United Russia party, and his son Alexei jointly own the condominium.
Pekhtin denied that he violated any laws and said the Russian opposition wanted to discredit the entire parliament and not just him.
"I do not want the unjustified accusations to cast a shadow over our party," he told a session of the State Duma, the lower house of parliament, in televised remarks.
"That is why I made a difficult decision -- I will say that honestly -- to resign the post of a State Duma deputy," he said.
Pekhtin, 62, called the documents showing his co-ownership of the US property an "obvious legal misunderstanding" which he promised to fight.
"I don't have the slightest doubt that I will prove that I am right," said Pekhtin who over the past days has become the subject of ridicule online.
"We will fight on," he said to applause from his colleagues.
The Russian opposition charges that the parliament dominated by United Russia lacks legitimacy because December 4 parliamentary polls were slanted in favour of the ruling party.
Claims of vote fraud brought tens of thousands into the streets across Russia last year and encouraged opposition activists to cobble together an anti-Kremlin protest movement.
Since Putin's return to the Kremlin for a third term in May, the parliament fast-tracked a number of controversial laws that critics say are designed to clamp down on the country's awakening civil society.
The opposition says Russian pro-Kremlin lawmakers are hypocrites because many of the recently adopted laws are anti-Western yet many of the deputies have secret property in Europe and the United States.
In recent months, Navalny and his allies have exposed several top officials whom they say own property in the West but Pekhtin is the first to resign over the claims.
The documents on Pekhtin's US property were provided to Navalny by a like-minded blogger, known by his nickname doct-z, who is a Russian physicist residing in Spain.
"To be fair, we have to admit that such a step by Pekhtin shows that he has the remnants of a conscience lingering somewhere deep down," Navalny wrote in his blog on Wednesday.
Pro-opposition commentators praised the result, saying that tactic would prove rewarding after the unprecedented protests largely died down.
"This is exactly what the opposition needs to do now -- this way they can put out of action half of the United Russia top brass," said Vladimir Pribylovsky, head of the Panorama think-tank.
Russian lawmakers and top officials are widely-known for their reluctance to step down over corruption allegations.
Analysts suggested that the party leadership had told Pekhtin to resign.
His colleagues praised his resignation as a bold move.
The parliament is now debating amendments to a law that would protect personal privacy in a move critics say is aimed at shielding lawmakers from anti-corruption investigations by the opposition.
Another United Russia lawmaker, Anatoly Lomakin, whose fortune the Russian edition of Forbes magazine puts at $1.2 billion, plans to resign because of ill health, officials said later Wednesday.