"Any characterization that somehow we have improperly challenged Russian aggression or have somehow tried to encroach on their legitimate interests is just wrong. And Mr. Trump's continued flattery of Mr. Putin and the degree to which he appears to model many of his policies and approaches to politics of Mr. Putin is unprecedented in American politics," Obama said at a joint news conference with Italian Prime Minister Matteo Renzi.
"It is out of step not just with what Democrats think but out of step with what up until the last few months almost every Republican thought, including some of the ones who are now endorsing Mr. Trump," Obama added.
He also criticized Republicans who were "constantly haranguing us for even talking to the Russians" and are now supporting Trump and his position of engagement.
"Mr. Trump rarely surprises me these days. I'm much more surprised and troubled by the fact you have Republican officials who historically have been adamantly anti-Russia and in fact have attacked me for even engaging them diplomatically now supporting, in some cases echoing his positions. It's quite a reversal," Obama said.
"You'll have to ask them how to explain that."