Trump said he has "low expectations" of the summit and "maybe some good will come of it". "I don't know what's going to happen, but I can tell you what I'll be asking for and we'll see if something comes of it".
And which is relevant because Trump is meeting with Putin on Monday, despite the fact that special counsel Robert Mueller indicted a dozen Russians on Friday due to their connections to the election meddling operation.
The United States does not have an extradition treaty with Russian Federation.
In the interview Trump told CBS that he had not thought about asking Putin to hand over the 12 Russians indicted for alleged interference in the U.S. elections of 2016.
The president taped the interview Saturday in Scotland, a day before he was set to leave for Helsinki for the summit. Clinton, Trump's opponent in the 2016 presidential election, tweeted on Sunday night.
Trump says he will "firmly" ask Putin about election interference during the Helsinki summit.
Trump is under heavy pressure to tell Putin to stay out of USA elections when they meet, and he said Friday that he would.
The meeting comes just days after 12 Russian intelligence officers were charged by a USA federal grand jury for hacking the Democrats ahead of the 2016 election.
Asked whether Trump would ask Putin to turn over the 12 military intelligence officials, USA national security adviser John Bolton called the idea "pretty silly" and said doing so would put the president in a "weak position".
Mr Trump's explosive admission about the European Union also comes after the British Prime Minister Theresa May revealed that the controversial U.S. president offered her a very blunt piece of advice in regards to Brexit on his visit: Sue the European Union, don't negotiate. "So, we could do something to substantially reduce them - I mean, ideally get rid of them".
"We'll be talking about Syria", he said.
Trump's warm words for Russian Federation were a marked contrast from the past week when he repeatedly rebuked traditional USA allies at a summit of North Atlantic Treaty Organisation and during a visit to Britain.
He said: "I think the European Union is a foe, what they do to us in trade".
"That is what the American side proposed and we are polite people, so we have agreed", Russian Foreign Minister Sergei Lavrov said in a recent interview for Larry King's "Politicking", which airs on the Russia-backed RT network. "But - and this may be wrong - but they had much stronger defenses", Trump said.
"Vladimir Putin is a trained KGB agent".
Trump congratulated Putin for hosting the "truly great" tournament.
After Russia moved its military into Ukraine and annexed Crimea in 2014, the United States and other nations instituted a series of economic sanctions against Russia that remain in place over Putin's protests.
Donald Trump has rattled allies once more by labelling the European Union a "foe".
Republican Senator Lindsey Graham said Trump's performance sent a message of "weakness" to Moscow.
On Sunday, her 19-year-old son, Ewan Hope, was quoted in The Sunday Mirror as saying: "I don't share Donald Trump's politics and I'll never be a supporter of his, but I would like him to raise mum's case with the Russian president. We're going into negotiations with them".