A group in Russia has urged President Vladimir Putin to stay on as "national leader" after his term ends next March.
Mr Putin has made it clear he wishes to remain active in politics
The recently formed For Putin group said it had a petition with 30m signatures supporting such an idea.
It is unclear how the group's proposal can be implemented, as Russia's constitution prevents Mr Putin from seeking a third consecutive term.
Meanwhile, liberal opposition parties accused the authorities of harassment ahead of general elections in December.
Yabloko and the Union of Right Forces (SPS) said their members were being intimidated and campaign literature seized in the run-up to the 2 December poll.
A Kremlin spokesman denied the accusations.
'Laws can be changed'
For Putin called on the president to stay on as national leader at the group's first congress in the city of Tver, about 160km (99 miles) north-west of the capital Moscow.
"The constitution is a law and laws can be changed. It is only laws made by God that can't be changed," group activist Vladimir Voronin told some 700 delegates attending the congress.
A number of speakers in Tver praised Mr Putin's handling of Russia's economy and his political skills, and also wished him good health.
For Putin says it represents the fervent hope of millions of ordinary Russians who want the current president to stay on in power after his second term expires on 2 March.
The group's leadership says it is completely independent of the Kremlin and of any Russian political party.
But it seems extremely unlikely that the group could have grown so fast without at least the tacit support of the Kremlin, the BBC's Rupert Wingfield-Hays in Tver says.
What seems more likely, our correspondent adds, is that it represents the deep anxiety of Russia's power elite, which views the end of the Putin presidency with growing concern.
It is not clear how Mr Putin can stay on as national leader when another man is sitting in the Kremlin as Russia's next president.
But some For Putin delegates hinted that Mr Putin could take any number of jobs - from prime minister, to prosecutor general or head of the Supreme Court.
SPS wants Mr Putin to be disqualified from the polls
Mr Putin has repeatedly stated that he wants to remain an influential political player after next March.
Earlier this year, he agreed to head the electoral list of the pro-Kremlin United Russia party, saying he may seek to become prime minister.
Russia's opposition questions the legitimacy of the move - the SPS party has already asked Russia's Supreme Court to remove Mr Putin from the United Party list.
The lawsuit is likely to be symbolic, correspondents say.
SPS leader Nikita Belykh alleges that since Mr Putin has agreed to lead the United Russia list, the "might of the state bureaucratic machine" has fallen on the liberal party.
Mr Putin, a former KGB officer, came to power in 2000.
His supporters praise him for stabilising Russia after economic and political upheavals of the 1990s and also for raising the country's prestige.
Critics accuse the president of clamping down on media freedoms and undermining democratic reforms that were launched soon after the collapse of the Soviet Union in 1991.