"I have great confidence in my intelligence people". And following the president's press conference, Director of National Intelligence Dan Coats again reaffirmed that the intelligence community's assessment remains unchanged.
He revealed that he had not thought about asking for the extradition of 12 Russians indicted for allegedly meddling in the 2016 presidential election.
A joint press conference now confirmed by the US will be the last event on the schedule.
Some career diplomats also expressed alarm.
"I appreciated your support", Trump said. "I think we have great opportunities together as two countries because frankly, we have not been getting along well for the last number of years".
After their "personal" talks, Putin and Trump will then each be joined by their top team of aides before giving another press conference.
Konstantin Kosachev, head of the upper house of parliament's foreign affairs committee, wrote in Izvestia that Monday's talks come at a time when "so-called "peace-loving" Europe is afraid of peace talks between US and Russian Federation".
"The president must appreciate that Russian Federation is not our ally", Ryan said, in what was, for the mild-mannered speaker, akin to a reprimand.
Donald Trump met one-on-one with Vladimir Putin behind closed doors on Monday in a long-awaited summit overshadowed by the US president blaming his own country's past "foolishness and stupidity" for the two powers' hostile ties.
Russian Federation denies the allegations, and says it is looking forward to the talks as a vehicle for improving relations. It gave no further details.
Trump heads into the summit with little clear agenda other than to strengthen his personal rapport with Putin, which he thinks is crucial to improving relations between Washington and Moscow.
Moscow would love to have US sanctions - initially imposed over the Crimea annexation - eased and eventually lifted.
The Russian foreign ministry "liked" his words and tweeted back: "We agree".
At the news conference, Trump was invited by reporters to offer any criticism of Russian Federation, but he repeatedly declined.
In 1975, the USA and Russian Federation - then the key power in the Soviet Union - along with 33 other states, signed a major agreement in Helsinki to defuse Cold War tensions. I think the US has been foolish. "We need to get justice for my mum".
President Donald Trump says the testimony of an FBI agent who was removed from the special counsel's Russian Federation investigation was "an absolute disgrace".
The meeting came in the midst of tensions between Russian Federation and the West in issues concerning Iran, Syria and Crimea, as well as the unprecedented alienation between the USA and its trans-Atlantic allies over trade and defense. It doesn't mean anything, it means that they're competitors. Putin claims that the Obama administration fomented the pro-Western revolution in Kiev that year in a bid to weaken Russian influence, and that Russia needed to take over Crimea to protect Russian speakers on the Black Sea peninsula.
Ahead of the talks, Trump has refused to personally commit to the United States refusal to recognise Russia's annexation of Crimea, leaving open the possibility of a climb-down linked to a promise by Putin to somehow rein in Iranian influence in Syria.
Asked whether he had wanted Trump to win the 2016 election and had instructed officials to help him, Putin said: "Yes I did", although he denied any interference, saying the allegations were "complete nonsense". Instead, Paul said Trump and other USA officials should focus on safeguarding upcoming elections from interference. And he chastised British Prime Minister Theresa May for not pursuing a "hard" enough break with the E.U.in Brexit talks and for dismissing his advice.
Asked what he will say to Putin Monday, Trump said, "We'll do just fine".