"For years presidents have been coming to these meetings and have talked about the tremendous expense to the U.S., and tremendous progress has been made", Mr Trump said.
Trump will meet the Russian leader in Helsinki on July 16 for their first summit amid an ongoing investigation in the U.S. into possible Trump campaign collusion with Russia.
"The aim of this meeting is to begin setting right the negative state of bilateral relations, to agree on concrete measures to improve them and to establish a more or less acceptable level of trust", Ushakov said. "It's been unbelievable to see the level of spirit in that room".
Trump reiterated Friday that he is not going into the meeting with high expectations, but he said the two leaders would also discuss "a number of things", including cuts to nuclear weapons arsenals.
In the meantime, President Donald Trump has arrived in Great Britain for his first visit as president amid North Atlantic Treaty Organisation tensions, protests and Brexit turmoil.
But just days out from a high-stakes meeting with Russian President Vladimir Putin in Helsinki, the mercurial USA leader threatened to throw the transatlantic alliance into disarray.
"Start treating Putin like you do with the Democrats - tough, strong, 'we're not going to take your nonsense", he said.
Earlier Friday during a press conference overseas with his British counterpart, Trump vowed to press Putin about his government's interference in the 2016 American election - though he appeared to leave open, as always, the possibility that he won't.
Trump also singled out Germany and its chancellor Angela Merkel for criticism, a day after saying Berlin had become a "captive of Russia" because of a gas pipeline deal and should be paying more for defense.
And while the president has said he ultimately wants to up commitments doubled to 4 percent, for now he said that countries have agreed to move at a "faster clip" to meet the 2 percent threshold. Some NATO allies had not exactly heard the same conclusions as Trump around the table, and French President Emmanuel Macron immediately poured cold water on Trump's spending ambitions for other allies.
Trump heads to Britain on Thursday, where the government is in crisis over Brexit and where tensions with Russian Federation have spiked after London blamed Moscow for the death this month of a British woman from contact with the Novichok nerve agent. Just make sure we can trade together. "I just don't know". According to Ushakov, Putin will meet with the leaders of the two countries that qualified for the World Cup final - Macron and Kolinda Grabar-Kitarovic - ahead of the match, which will be held at Moscow's Luzhniki Stadium on Sunday.
Trump has described the spending situation as "disproportionate and not fair to the taxpayers of the United States". But the GDP growth historically fluctuates by year: The four best years under Obama, for example, were 2.9 percent real growth in 2015, 2.6 percent in 2014, 2.2 percent in 2012 and 2.5 percent in 2010.
"That's all." In the end, leaders left with an awkward consensus, after hours in which Trump had been so aggressive in his approach with allies that reports made the rounds that he might pull the USA out.
Including that commitment, however, Canada's current defence spending plans are only expected to bring it to 1.4 per cent of GDP by 2024 - well short of the Wales target.