U.S. Secretary of State Mike Pompeo told Russia on Tuesday that Washington would brook no interference in the 2020 U.S. presidential election and wanted Moscow to take action to show there would be no repeat of its suspected 2016 meddling.

President Vladimir Putin, who met Pompeo in the Russian Black Sea resort of Sochi, pushed back, telling him that Russia never interfered in U.S. elections and that a report by U.S. Special Counsel Robert Mueller, which he praised as being “objective overall”, had found no evidence of collusion with President Donald Trump’s 2016 campaign.

Relations have long been strained by U.S. intelligence and law enforcement findings - denied by Moscow - that Russia tried to influence the results of the 2016 U.S. presidential election to boost Trump’s chances of winning the White House.

Pompeo’s visit followed the publication of the long-awaited report by Mueller into the nature of Russia’s role in that election that spoke of “sweeping and systematic” interference by Moscow but did not establish that members of Trump’s campaign conspired with Russia during the 2016 election.