President Trump expressed doubt about the accuracy of U.S. spy agencies and prosecutors that accuse Russia's government of intervening in the 2016 U.S. election to help him win.

Trump, speaking at a joint press conference in Finland with Russian President Vladimir Putin, defiantly said he retains an open mind about possible Russian culpability.

"I have President Putin, he just said it is not Russia. I will say this. I don't see any reason why it would be," Trump said.

Later, Trump said, "As you know, the whole concept of that came up perhaps a little bit before, but it came out as a reason why the Democrats lost an election, which frankly they should have been able to win because of the Electoral College."

[Related: Trump dismisses Russian election meddling, doesn't see 'any reason' for it]

Trump opened the press conference saying Putin had an "interesting idea" relating to alleged Russian interference, potentially referring to a subsequent Putin offer to facilitate interrogations of 12 Russian officials indicted last week for allegedly hacking Democratic emails.

At one point Trump said, "I have great confidence in my intelligence people but I will tell you that President Putin was extremely strong and powerful in his denial today and what he did is an incredible offer. He offered to have the people working on the case come and work with their investigators with respect to the 12 people. I think that's an incredible offer. Thank you."

Trump and Putin spoke for about two hours before the press conference, which concluded with Trump invoking the Thursday testimony of FBI official Peter Strzok as evidence that the investigation of possible campaign collusion with Russia is "a total witch hunt."

Asked if he believes U.S. government assessments of Russian election interference, Trump launched into a discussion of the FBI being unable to access the server of the Democratic National Committee, which allegedly was hacked by Russia. He also mentioned an investigation into the conduct of a House Democratic IT staffer, though that case is not publicly known to be connected to Russia.

"You have groups wondering why the FBI never took the server, why haven't they taken the server, why was the FBI told to leave the office of the Democratic National Committee? I've been wondering that and asking that for months and months and I've been tweeting it out and calling it out on social media. Where is the server? I want to know where is the server and what is the server saying?" Trump said.

He continued: "With that being said, all I can do is ask the question, my people came to me, [director of national intelligence] Dan Coats came to me and some others saying they think it's Russia. I have President Putin, he just said it is not Russia. I will say this. I don't see any reason why it would be, but I really do want to see the server."

Trump repeatedly said there was "no collusion" between his campaign and Russia.

"What happened to the servers of the Pakistani gentleman that worked on the DNC? Where are those servers? They're missing. Where are they? What happened to 33,000 emails of Hillary Clinton just gone? I think in Russia they wouldn't be gone so easily. I think it is a disgrace that we can't get Hillary Clinton's 33,000 emails," Trump said.

Trump has long bristled at suggestions that Russia intervened to help him defeat Clinton, often calling the official investigation into possible collusion between his campaign and the Kremlin a "witch hunt." At some points in time, however, he has appeared to accept the conclusion of U.S. intelligence agencies that Putin's government intervened.

Putin publicly denied Russian government interference on Monday, saying in his opening remarks at the press conference that the accusations were untrue, but his denials were briefer than Trump's remarks. At one point, Putin invoked George Soros, the billionaire political activist and donor, to say that it's possible Russians without government sponsorship hacked emails.

[John Bolton: Hard to believe Putin didn't know about any effort to hack Democratic emails, servers]

"Once again, President Trump mentioned the issue of the so-called interference of Russia in the American elections, and I had to reiterate things I said several times, including to our personal contacts," Putin said. "The Russian state has never interfered and is not going to interfere into internal American affairs, including the election process."

[Also read: Russia: Mueller trying to sabotage Trump-Putin summit]