Washington, Jul 17 (IANS): US President Donald Trump is facing a barrage of criticism for defending his Russian counterpart Vladimir Putin over claims of Moscow's interference in the 2016 presidential elections.

At a joint news conference with Putin following their summit in Finland on Monday, Trump refused to denounce the Russian leader for interfering in the presidential campaign and instead contradicted American intelligence agencies, the US media reported on Tuesday.

Russia had no reason to meddle, Trump said.

His remarks sparked an enormous amount of backlash from his critics, Republicans and Democrats, warning that his actions could ultimately hurt national security interests.

"The President must appreciate that Russia is not our ally," said House Speaker Paul Ryan. "The US must be focused on holding Russia accountable and putting an end to its vile attacks on democracy."

Russia is responsible for "ongoing, pervasive attempts" to undermine US democracy, said Director of National Intelligence Dan Coats.

Republican Senator John McCain, a key member of the Senate Armed Services Committee, said it was a "disgraceful performance".

"No prior President has ever abased himself more abjectly before a tyrant," he said.

Republican Senator Lindsey Graham tweeted that it was a "missed opportunity... to firmly hold Russia accountable for 2016 meddling".

"Shameful," tweeted Republican Senator Jeff Flake. "Bizarre and flat-out wrong," wrote Senator Ben Sasse in reference to Trump's separate assertion that both countries were to blame for their deteriorating relationship.

Senate Democratic leader Chuck Schumer said Trump's actions had "strengthened our adversaries while weakening our defences and those of our allies".

Former Vice President Joe Biden said: "... Our President had the chance to confront an adversary who has attacked - and continues to attack - our democracy and our allies. He could have stood up for American interests and values. He chose not to."

House Minority Leader Nancy Pelosi called Trump's performance an "embarrassment".

Former CIA director John Brennan said Trump's news conference "was nothing short of treasonous".

"Not only were Trump's comments imbecilic, he is wholly in the pocket of Putin. Republican Patriots: Where are you???" he tweeted.

Meanwhile, Vice-President Mike Pence defended the summit and praised Trump.

During the press conference, Putin offered to allow US investigators to visit Russia to question the officers regarding poll medding.

In a later interview with Fox News, he said it was "ridiculous" that some people thought Russia could have influenced the US elections.

Putin said the US-Russian relations should not be "held hostage" to an internal political struggle in America.

He also dismissed longstanding reports that Russian intelligence may hold compromising material on Trump.

The Russian leader described the Helsinki meeting as "candid and useful" while Trump said there had been "deeply productive dialogue".

Trump said US-Russia relations had "never been worse" than before they met, but that had now changed.