US president Donald Trump has defended his much-criticised performance at the Helsinki summit with Vladimir Putin, promising “big results” from better relations with Russia and hitting back at “haters”.

In a series of early tweets, Mr Trump wrote: “So many people at the higher ends of intelligence loved my press conference performance in Helsinki.”

The US leader said he and his Russian counterpart had discussed many important subjects, adding: “We got along well which truly bothered many haters who wanted to see a boxing match.”

Mr Trump also adopted a term some of his defenders and conservative media have applied to his critics, saying in a tweet that “it’s called Trump Derangement Syndrome!”

He made no mention of his having walked back comments that called into question US intelligence findings of Russian meddling in the 2016 presidential election.

Those comments, delivered alongside Mr Putin at a summit press conference on Monday, had prompted blistering, bipartisan criticism at home.

In a follow-up tweet, Mr Trump wrote that Russia has agreed to help in delicate negotiations with North Korea, although he provided no details on how and when that would happen.

“Big benefits and exciting future for North Korea at end of process!” he wrote.

Amid bipartisan condemnation of his embrace of a long-time US enemy, Mr Trump sought to end 27 hours of recrimination by delivering a rare admission of error on Tuesday.

He backed away from his public undermining of American intelligence agencies, saying he mis-spoke when he said he saw no reason to believe Russia had interfered in the 2016 US election.

Addressing comments he had made standing alongside Mr Putin on the summit stage in Helsinki, Mr Trump said: “The sentence should have been, ‘I don’t see any reason why I wouldn’t, or why it wouldn’t be Russia'”, instead of “‘why it would’.”

That did not explain why Mr Trump, who had tweeted half a dozen times and sat for two television interviews since the Putin news conference, waited so long to correct his remarks. The scripted clean-up pertained only to the least defensible of his comments.

Protests outside the White House
Center for American Progress President Neera Tanden speaks at a protest outside the White House (AP)

He did not reverse other statements in which he gave clear credence to Mr Putin’s “extremely strong and powerful” denial of Russian involvement in collusion, raised doubts about his own intelligence agencies’ conclusions and advanced discredited conspiracy theories about election meddling over the 2016 poll that put him in the White House.

Mr Trump also accused past American leaders, rather than Russia’s destabilising actions in the US and around the world, for the souring of relations between two countries.

He did not address his other problematic statements during a week-long European tour, in which he sent the Nato alliance into emergency session and undermined Prime Minister Theresa May as she hosted him for an official visit.

Mitch McConnell
Mitch McConnell publicly reassured America’s European allies after Mr Trump’s controversial visit (AP)

“I accept our intelligence community’s conclusion that Russia’s meddling in the 2016 election took place,” Mr Trump conceded on Tuesday. But even then he made a point of adding: “It could be other people also. A lot of people out there. There was no collusion at all.”

Moments earlier, the usually reserved Senate majority leader, Mitch McConnell, publicly reassured America’s allies in Europe following Mr Trump’s clashes with them during his trip last week.

“The European countries are our friends, and the Russians are not,” Mr McConnell declared.

Senate Democratic leader Chuck Schumer said Mr Trump was trying to “squirm away” from his comments made alongside the Russian president.

“It’s 24 hours too late and in the wrong place,” he said.