Russia has threatened to block access to YouTube and Instagram if the websites do not remove videos and photos of a Kremlin-linked oligarch’s meeting with a senior government minister on a luxury yacht.

The meeting between Oleg Deripaska, an aluminium and mining tycoon, and Sergei Prikhodko, a Russian deputy prime minister, was the subject of a recent investigation by Alexei Navalny, the Russian opposition figurehead.

Navalny’s investigation was based on footage and photographs posted to Instagram in 2016 by Anastasiya Vashukevich, a 21-year-old model and escort who goes by the name Nastya Rybka. Vashukevich said she had been hired to spend time with the men on the yacht on a trip off the coast of Norway.

“An oligarch takes a top government official on a ride on his own yacht – that’s a bribe,” Navalny said in a video that has had more than 4m views. “An oligarch pays for all of this, including young women from escort agencies. Believe it or not, that is also a bribe.”

Navalny also alleged, without offering proof, that Deripaska was briefing Prikhodko on information on the 2016 US presidential campaign that he had received from Paul Manafort, the former Trump campaign manager.

Manafort, who has had business dealings with Deripaska, offered private updates to the oligarch on Trump’s election campaign in a 2016 email, the Washington Post reported last year. Deripaska says he was not contacted by Manafort about such briefings.