Taking to Twitter Monday morning, the president said, "Our relationship with Russian Federation has never been worse thanks to many years of U.S. foolishness and stupidity and now, the rigged witch hunt!"
Asked to name the U.S.'s "biggest foe globally" in an interview conducted Saturday and aired Sunday on CBS's "Face the Nation", Trump first mentioned the European Union, adding that "we have a lot of foes".
Prior to their private meeting, Trump and Putin appeared before members of the media.
The Helsinki summit is the capstone to a almost week-long trip for Trump during which he has sown doubts about his commitment to the North Atlantic Treaty Organisation military alliance, Washington's so-called special relationship with Britain and USA relations with the European Union that he called "a foe" on trade.
Putin and Trump are due to participate in one-on-one talks and a working lunch before attending a joint press conference.
Putin said before Trump spoke that Moscow never interfered and will never interfere in the American electoral process. He has repeatedly noted that Putin denies it, while also saying that it is alleged to have taken place before he became president.
The US and Russian Federation were the "two great nuclear powers", Trump added.
"You know I love those countries".
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Deschamps, who became the third person to win as both a player on the field and a coach on the bench, looked like he loved it. The team's appearance on the Champs-Elysees will be followed by a reception at the presidential palace.
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I don't think over the six or seven weeks we've been together now that they could have given any more'. "They know we've got beaten but we've come so far".
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Froome trails race leader Greg Van Avermaet by 1:02. "I was picking wheels and seemed to be in a good position", Cavendish said. Although Van Avermaet retains yellow for now, it was in truth a dismal day for BMC.
But Trump didn't direct his tough words toward Russian Federation, the aggressor.
But after being given the idea by his interviewer, President Trump said: "Certainly I'll be asking about it".
"That's all." Ahead of the Helsinki summit, European officials say they fear Trump more than Russian President Vladimir Putin.
Ahead of his meeting in Britain, Trump criticized Prime Minister Theresa May's approach to negotiations about Britain leaving the European Union and suggested it could impact a proposed trade deal between London and Washington.
"We have not been getting along well for the last number of years", Trump said as he and Putin sat down at the Presidential Palace in Finland's capital.
"There are enough of them for us to start paying attention", he said, sitting next to Trump before they shook hands.
Niinistö also called attention to the importance of establishing and fostering a dialogue between the two heads of state. Big banners said "Welcome Trump" and "God Bless D & M Trump" and a helicopter hovered overhead.
During the 2016 presidential campaign, Clinton expressed similar sentiment about the Trump-Putin relationship.