As President Donald Trump continues to dispute the presidential election results, there has been special attention paid to how world leaders have reacted. To little surprise, Russian President Vladimir Putin has not accepted the results or recognized Joe Biden as the president-elect, claiming that the outcome isn't official or legitimate.

Putin on Sunday explained his opinions on state-run television, Bloomberg noted.

“We will work with anyone who has the confidence of the American people. But that confidence can only be given to a candidate whose victory has been recognized by the opposing party, or after the results are confirmed in a legitimate, legal way," Putin said.

Results of the presidential election are not official but Biden won 306 electoral college votes and received over 6 million more votes than Trump. Trump has sought legal challenges to some states' vote counts.

Russia reportedly fears that clashes of human rights and sanctions pressure will increase with Biden in office, but Putin claims he is willing to work with him if he’s president-elect. There have been no congratulations given to Biden from Putin, but Putin believes that’s just a formality and there’s nothing more behind that reason.

There has been increased tension between the U.S. and Russia in recent years. The U.S. in 2014 imposed sanctions on Russia in response to its invasion of Ukraine. After years of investigations, a Senate report in April confirmed the U.S. intelligence assessment that Russia interfered in the 2016 election to help Trump win the presidency.

When asked if no congratulations would cause issues for U.S.-Russia relations, Putin said, “there’s nothing to damage, they’re already ruined,” the Hill reports.

Russia political analyst Anton Barbashin told CNBC on Nov. 9 that it's bad for the Kremlin that Biden won.

″(The) Kremlin is well aware that Biden and even more so his team are highly determined to be considerably more assertive when it comes to countering Russia’s influence in Europe, Russia’s near-abroad and international arena as well,” Barbashin said.

Putin's comments come as the Trump administration announced it would withdraw from the Open Skies Treaty. The arms control pact was signed in 1992 to allow unarmed, reconnaissance flights over two countries' territories to collect information on military forces.

This is the second treaty the Trump administration has withdrawn from. In August, the U.S. withdrew from the Intermediate-range Nuclear Forces Treaty that was signed in 1987.

Then US vice president Joe Biden (left) meets in 2011 in Moscow with Russia's now president, Vladimir Putin, who has formed a controversial relationship with US President Donald Trump
Then US vice president Joe Biden (left) meets in 2011 in Moscow with Russia's now president, Vladimir Putin, who has formed a controversial relationship with US President Donald Trump POOL / ALEXEY DRUZHININ