A chorus of government officials from both sides of the political aisle have condemned Donald Trump's press conference with Vladimir Putin.

Conservative John McCain, who is facing a rare and terminal brain cancer, unleashed a damning statement against Mr Trump’s conference with Mr Putin, describing it as “one of the most disgraceful performances by an American president in memory”.

“President Trump proved not only unable, but unwilling to stand up to Putin,” he said.

“It is tempting to describe the press conference as a pathetic rout — as an illustration of the perils of under-preparation and inexperience. But these were not the errant tweets of a novice politician. These were the deliberate choices of a president who seems determined to realise his delusions of a warm relationship with Putin’s regime without any regard for the true nature of his rule, his violent disregard for the sovereignty of his neighbours, his complicity in the slaughter of the Syrian people, his violation of international treaties, and his assault on democratic institutions throughout the world."

The conservative senator's comments arrived after the US president declined to name Russia as the adversary behind coordinated attacks on the 2016 presidential election.

While discussing whether he thought Russia was behind hacks against the 2016 election — as the US intelligence community has determined —the president said: "I don’t see any reason why it would be."

“Dan Coats [the US Director of National Intelligence] said its Russia. President Putin says its not Russia,” said Mr Trump. “I don't know why it would be…..I have confidence in both parties. President Putin was extremely strong and powerful in his denial today.”

That set off a wave of condemnations from Democrats and Republicans alike.

"President Trump’s press conference with Putin was an embarrassing spectacle," Bernie Sanders wrote in a tweet. "Rather than make clear that interference in our elections is unacceptable, Trump instead accepted Putin’s denials and cast doubt on the conclusions of our intelligence community. This is not normal."

Jeff Flake, one of the only frequent Republican critics of Mr Trump in Congress, said the conference was “shameful” in a statement he posted across social media.

"I never thought I would see the day when our American President would stand on the stage with the Russian President and place blame on the United States for Russian aggression,” he said. “This is shameful."

Former CIA Director John Brennan released a statement calling for Mr Trump's impeachment and describing his comments as "treasonous".

"Donald Trump’s press conference performance in Helsinki rises to & exceeds the threshold of 'high crimes and misdemeanours,'" Mr Brennan wrote on Twitter. "It 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???"

Elizabeth Warren also slammed the president for failing to hold Mr Putin accountable, writing on Twitter: "Russia interfered in our elections & attacked our democracy. Putin must be held accountable – not rewarded."

"Disgraceful," she concluded.

However, Mr Trump’s typical roster of critics weren’t the only legislators rebuking his bizarre denials of US intelligence. Lindsey Graham also criticised Mr Trump’s performance, adding that his denial of US intelligence will “be seen by Russia as a sign of weakness and create far more problems than it solves”.

“Missed opportunity by President Trump to firmly hold Russia accountable for 2016 meddling and deliver a strong warning regarding future elections,” he said.

The Republican senator added a suggestion to Mr Trump: review the soccer ball Mr Putin gave to him as a gift for “listening devices” and “never allow it in the White House.”

Thomas Pickering, a regarded statesman and the former US ambassador to Russia, told MSNBC that he was in utter disbelief after the press conference was held on Monday.

“It's a breathtaking denial of something that clearly is so obviously true,” he said. ”it represents the epitome of President Trump’s effort at self-promotion over the notion of defending the national interest of the United States."

Mark Warner, a Virginia senator, also suggested Mr Trump committed a clear violation of his responsibilities as president.