Russian pranksters claim they called U.S. Democratic presidential candidate Bernie Sanders pretending to be climate activist Greta Thunberg and offered Thunberg's support to his campaign.

Vladimir Kuznetsov and Alexey Stolyarov, who have fooled many high-profile victims around the world, posted a recording of the phone call on YouTube on Thursday.

The call itself took place in early December, but the duo decided to release it more than two months later because of Sanders' success in Iowa and New Hampshire, Kuznetsov told the Associated Press in a Skype interview.

In the recording, an unnamed female pretends to be Greta, and Stolyarov plays her father, Svante.

Bernie Sanders is seen in an animation that accompanies the prank phone call, in which Russian comedians pose as Greta Thunberg and offer to endorse him

In the call, 'Greta' then proposes to record 'a cool rap' song in support of Sanders

They offer to lend support to the campaign of a man who identifies himself as Sanders, and the man welcomes it.

The 78-year-old Sanders suggests that 'Greta' make a statement in his support and that they do an event together when she next comes to the U.S. 'I would be really appreciative,' he says.

'Greta' then proposes to record 'a cool rap' song in support of Sanders together with 'singer Billie Eilish and rapper Kanye West.'

'If we want to make the video successful, we need to put there a lot of expensive cars, and girls,' says 'Greta'.

'And you need to wear gold jewelry and chains, it will be nice,' she adds.

Sanders laughs and says 'Okay' as he tries to end the conversation, but the duo says 'Greta' is about to visit Russia and needs advice on how to behave there.

'If we want to make the video successful, we need to put there a lot of expensive cars, and girls,' says 'Greta'. Above, the pranksters imagine what the rap video would look like

'Greta' tells Sanders that 'singer Billie Eilish and rapper Kanye West' (left and right above) would be willing to join her in recording a cool rap video endorsing his campaign

Vladimir Kuznetsov (left) and Alexey Stolyarov (right) who have fooled many high-profile victims around the world, posted a recording of the phone call on YouTube on Thursday

The Vermont senator tells her to be careful to not be used for PR purposes. 'I think what you don't want to do is simply walk in there and get used,' he says.

'Russia and (President Vladimir) Putin has been very bad, as far as I know, on climate change. They have a lot of oil, oil is important for their economy, they make a lot of money on oil,' Sanders explains.

After that, 'Greta' tells Sanders that he was recruited by the KGB in 1988 when he visited Russia and has since been a 'sleeper agent.'

'Now it´s time to wake up and fulfill your mission, become president of the United States, build communism in the United States and work for Russia!' she says, after which Sanders appears to hang up the phone.

A representative for the Sanders campaign didn't comment Friday on the authenticity of the call.

Federal law enforcement officials were alerted in November that several Democrats had received calls from someone believed to be outside the U.S. who was claiming to represent the teenage Thunberg and was trying to set up calls or in-person meetings with members of Congress, a U.S. official said.

Sanders speaks at a campaign event in Durham, North Carolina on Friday

Some of the congressional offices reported the incidents to the FBI and the Capitol Police, the official said. The person was not authorized to discuss the matter publicly and spoke on condition of anonymity.

Kuznetsov told AP that the call was one of many in the comedy duo's new project dubbed 'Stars Save the Earth,' in which they call high-ranking politicians and celebrities pretending to be Thunberg.

'Many laugh at Bernie Sanders (and say) that he is a KGB agent and wants to build communism in the U.S. Since he calls himself a democratic socialist, we decided to play up this topic - the topic of Sanders being a recruited Russian agent,' Kuznetsov said.

Stolyarov added that Thunberg's name 'opens doors to everyone.' 'Everyone, from presidents to street cleaners, are ready to talk to Greta Thunberg,' he told the AP in a Skype interview.

Stolyarov insisted the pranksters didn't want to influence the presidential race in the U.S. in any way. In previous years, the two have been accused of having ties to the Kremlin -- a notion they have repeatedly denied.

Kuznetsov said they didn't expect any repercussions for the prank. 'It's not illegal, and we're well known in the U.S.,' he said.