"Those are the worst reviews I've seen since Titanic", Colbert said.
Mr Trump said: "I realise there's a need for some clarification", adding that what he meant "should have been obvious - I thought it would be obvious but would like to clarify in case it wasn't".
After the summit, Trump reiterated his stance.
What did he say at the summit with Putin?
"It's a shame, we're talking about nuclear proliferation and Syria, and humanitarian aide, and we get question on the witch hunt", Trump complained.
"President Putin says it's not Russian Federation".
Ryan's comments came after Trump said at a summit with Russian President Vladimir Putin that he sees no reason why Russia would interfere in the US election. "I don't see any reason why it would be", he replied. "Sure, on the one hand, Russian Federation messed with the USA by meddling in the elections, but on the other hand, America held elections, so they were asking for it".
Paul tells The Associated Press, "We should look for ways to make the dialogue better".
"I have felt very strongly that while Russia's actions had no impact at all on the outcome of the election, let me be totally clear in saying that - and I've said this many times - I accept our intelligence community's conclusion that Russia's meddling in the 2016 election took place", he said. "I think that the United States has been foolish".
Top administration officials have accepted this conclusion, such as former Central Intelligence Agency director Mike Pompeo who is now Mr Trump's secretary of state. And he said he "entirely" agrees with intelligence agencies' assessment that Russians meddled in the election.
Kimmel mocked the president for "spreading the blame around" by saying that others may have interfered with the election besides Russian Federation and for having to write that "There was NO COLLUSION" on his notes.
Republican House Speaker Paul Ryan said there was no doubt Russian Federation had meddled in U.S. elections and that Mr Putin "does not share our values".
Trump, whose summit with Putin concluded a week-long Europe trip that included a North Atlantic Treaty Organisation meeting and talks with British Prime Minister Theresa May, pushed back on Tuesday at the storm of criticism, blaming media coverage.
"First of all, he said there was no collusion whatsoever", POTUS said, turning to look directly at the camera and putting on his I'm Surrounded By Idiots In Washington face.
At the summit, Mr Putin again denied meddling in the U.S. election, and in a later interview dismissed longstanding reports that Russian intelligence may hold compromising material on Mr Trump.
However, Mr Trump found support from Republican Senator Rand Paul, who blamed "Trump derangement syndrome" for the criticism - prompting a supportive tweet from the president himself.