But Warner took it a step further than Senate Minority Leader Chuck Schumer (D-NY), suggesting to reporters on Friday that if Trump and Putin meet one-on-one, the Kremlin leader would likely take advantage of Trump's unpreparedness.
"Start treating Putin like you do with the Democrats - tough, strong, 'we're not going to take your nonsense", he said.
Trump belittled the idea of challenging the Russian president over election interference during a press conference on Friday just before the criminal charges were announced.
Trump has spent the weeklong trip wreaking havoc in Europe, first at a North Atlantic Treaty Organisation summit in Brussels where he questioned the value of the decades-old alliance, and later in Britain, where he faced fallout from a stunning newspaper interview in which he undermined British Prime Minister Theresa May at an especially vulnerable time.
Striking in the indictment is the stated finding that key sources of leaked information from the Democratic National Committee and the campaign of candidate Hillary Clinton-both DC Leaks and the hacker persona known as Guccifer 2.0-were both the creation and under the control of the GRU, the Russian government's cladenstine intelligence service.
"So you shouldn't buy Russian gas, you must stop energy cooperation with Russia and cooperate with the United States".
They had been told by the White House not to expect access to the president on Saturday.
Putin would introduce proposals in the economic sphere to Trump at the meeting, according to Ushakov.More news: United Kingdom minister to Trump: 'Where are your manners, Mr President?'
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In the most detailed USA accusation to date that Moscow meddled in the presidential election, a federal grand jury said Russian military intelligence agency officers covertly monitored computers of Clinton's campaign and Democratic campaign committees, and stole large amounts of data.
Then he quipped: 'There won't be a Perry Mason here, I don't think. "But considering the discussion among the European allies, not only the Americans, I think we need to ask ourselves consistently what more we can do".
Russian Federation has denied any involvement in the attack and rejected accusations that it interfered in the United States presidential election in a bid to help Trump win.
"What Trump does and says in America is a matter for the Americans".
And as Trump has talked about bringing Putin back into the global fold, the Treasury Department has continued to impose sanctions on various Russian officials, companies and businessmen.
Republican Senator Jeff Flake of Arizona, a frequent critic of the president, said Trump needs to do more than ask. "It makes it very hard to do something with Russian Federation".
"Today we have common threats, common enemies", Lavrov said.
Scuffles broke out at one point as attendees - who chanted slogans including "We love you Donald" - passed a nearby anti-fascism protest.
They are also accused of stealing the data of half a million voters from a state election board website, the BBC report said.