US President Donald Trump has said he accepts US intelligence agencies' conclusion that Russia interfered in the 2016 election - despite declining to do so just a day ago.

He said he had misspoken on Monday and had meant to say he saw no reason why it was not Russia that meddled.

The original comments, after he met Russian President Vladimir Putin in Helsinki, drew a barrage of criticism.

The controversy centres on a response he gave to a question at a news conference on Monday following the summit with Mr Putin.

This is an extract from the transcript posted by the White House.

REPORTER: President Putin denied having anything to do with the election interference in 2016. Every US intelligence agency has concluded that Russia did. My first question for you, sir, is, who do you believe?

TRUMP: My people came to me... they said they think it's Russia. I have President Putin; he just said it's not Russia. I will say this: I don't see any reason why it would be.

Mr Trump said he had reviewed the transcript and realised he needed to clarify.

"In a key sentence in my remarks, I said the word 'would' instead of 'wouldn't," he said.

"The sentence should have been: 'I don't see any reason why I wouldn't' or 'why it wouldn't be Russia'. Sort of a double negative."

The US president added: "I accept our intelligence community's conclusion that Russia's meddling in the 2016 election took place. Could be other people also. A lot of people out there."