US House speaker Paul Ryan has hinted that Donald Trump will not be given an easy ride as he meets members of Congress later to discuss his comments on Russia.
Mr Ryan, the top Republican in the House of Representatives, has previously been reluctant to criticise the US president but is among many who have been angered by Mr Trump's claim that the US' "foolishness and stupidity" is to blame for its poor relations with Russia.
In a news conference after meeting Vladimir Putin on Monday, Mr Trump also appeared to accept the Russian president's word over that of his own intelligence agencies regarding alleged Russian meddling in the 2016 US election.
His pliable manner at the summit with Russia was a contrast to the combativeness he had displayed towards NATO allies last week, and Mr Ryan felt the need to issue reassurance that the US "stands by NATO allies and all countries facing Russian aggression".
Just hours before Mr Trump's scheduled meeting with members of Congress, Mr Ryan suggested that the president will be rigorously questioned on his remarks.
Mr Ryan said: "Let's be very clear – Russia meddled in our election".
He said he was willing to consider additional sanctions on Russia and that Congress would make sure they were not able to "get away with (election meddling) again".
"Russia is a menacing government that does not share our interests and it does not share our values," he said.
Mr Ryan is not the only powerful Republican to have criticised Mr Trump's behaviour towards Russia – Senate foreign relations chairman Bob Corker, and former House speaker Newt Gingrich are among those who have joined in.
Mr Gingrich called the president's comments "the most serious mistake of his presidency" while Mr Corker said the remarks made the US "look like a pushover".
Mr Trump turned to Twitter to blame media coverage of the Helsinki meeting with the Russian leader, writing that the "fake news (has) gone crazy".
Mr Trump added: "I had a great meeting with NATO.
"They have paid $33 Billion more and will pay hundreds of Billions of Dollars more in the future, only because of me. NATO was weak, but now it is strong again (bad for Russia).
"The media only says I was rude to leaders, never mentions the money!"
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About 20 minutes later, he tweeted again: "While I had a great meeting with NATO, raising vast amounts of money, I had an even better meeting with Vladimir Putin of Russia.
"Sadly, it is not being reported that way – the Fake News is going Crazy!"