A pro-Kremlin channel accused Russian protest leader Alexei Navalny of taking money from abroad and having contacts with the CIA, in a sensationalist report based on bugged conversations aimed at smearing his reputation as a clean-cut corruption fighter.
The report was broadcast by the NTV channel, owned by state-controlled gas giant Gazprom, late Wednesday, one day after President Vladimir Putin had warned over a "fifth column" in Russia after its taking of Crimea.
The report, shown on the channel's "Emergency Incident" muck-raking documentary slot, accused Putin's most vocal critic of seeking money from European Parliament figures and meeting with the CIA.
In the first part, it showed closed-circuit TV pictures of Navalny arriving at a Moscow hotel last year to meet senior European parliament MP and former Belgian prime minister Guy Verhofstadt.
It claimed that the bugged conversation recorded in the hotel showed that Navalny was seeking financial backing from Verhofstadt.
"You are interested not just in the future of Russian politics... We need a kind of practical help in the investigation," a voice said to be that of Navalny tells the Belgian politician.
The television said a "concrete sum" was discussed but this was not mentioned in the recordings.
The second recording was a tapped phone call in which a voice said to be that of Navalny is heard discussing a "journey to the CIA" although the context is not immediately clear.
The television claimed that Navalny had been in touch with the CIA to make sure his name was not linked to money from foreign "sponsors".
The broadcast was a clear attempt at smearing Navalny, who has for years irked the Kremlin with in-depth corruption investigations into alleged hidden assets of the elite close to Putin.
Navalny was last year handed a five-year suspended sentence in a timber embezzlement case and is also being investigated on new charges of stealing from French cosmetics company Yves Rocher and a Russian firm.
The protest leader was in February put under house arrest in the second case and is no longer able to use the Internet and talk to the press.
His Twitter feed, one of the most followed sources of information of opponents of Putin, is now run by his wife Yulia.
She said they would be responding to the allegations later, dismissing the report as a "funny story" but saying followers should ask the security services how the conversations were recorded.
The report also coincided with the publication of an opinion piece by Navalny in the New York Times where he criticised the "malign intent" of Putin and his actions in Crimea.
But he said EU visa bans and asset freezes against Russian officials had gone nowhere near far enough.
"This action (the sanctions) is mocked in Russia and even seen as a tacit encouragement to Mr Putin and his entourage, who seem to possess some magical immunity," he wrote.
Navalny said those who should be hit include businessmen close to Putin like energy trader Gennady Timchenko and the billionaire Rotenberg brothers Arkady and Boris, Russian railways chief Vladimir Yakunin and the chief executive of the Rosneft oil firm Igor Sechin.
The NTV report also broadcast a recorded conversation said to have been between Navalny, his associate Vladimir Ashurkov and British Labour MP Emma Reynolds.
Navalny explains that he is avoiding foreign contacts as the Kremlin is using this against him. "I am never going to embassies, never meeting ambassadors," he explains. Reynolds says that she understands.
In another blow for the Russian opposition, the anti-Kremlin TV channel Dozhd (Rain) said it had been ordered to leave its premises by the owners, amid speculation that pro-Kremlin TV station Lifenews TV could take its place.
Putin's seizure of Crimea has so far gone down well in Russia, with the state-run VTsIOM pollster saying Thursday his approval rating was now 75.7 percent, its highest level for the past five years.
After rattling Putin with mass protests spearheaded by Navalny in 2011-2012, the opposition movement has now largely lost momentum. Russia's next presidential polls are not due until 2018.