Facing pointed criticism from increasingly disillusioned allies, he punched back, uncowed by the growing global outcry. He said a meeting could take place as soon as the United States was ready and that many European countries had offered their help in making it happen.
Moreover, later news came that Trump had not only mentioned the possibility of a meeting but also invited Putin to Washington.
"They should let Russian Federation come back in because we should have Russian Federation at the negotiating table", he said.
Putin has been driven closer to China by a sharp decline in relations with the West after Moscow's 2014 annexation of Crimea and support for a separatist insurgency in eastern Ukraine.
Trump's presidency has been clouded by a federal investigation into alleged Russian meddling in the 2016 presidential election, and possible collusion by his campaign.
The summit host, Canadian Prime Minister Justin Trudeau, kicked things off without waiting for those he described as "stragglers" to arrive.
Mr Trump was already at odds with the rest of the group - the UK, Canada, France, Germany, Italy and Japan - over the imposition of tariffs on steel and aluminium. The European Union also attends.
Putin meanwhile said Russian Federation would work with China on the North Korean nuclear issue, ahead of the highly anticipated meeting between US President Donald Trump and North Korean leader Kim Jong-un in Singapore.
Prime Minister Theresa May meeting Canadian Prime Minister Justin Trudeau at the G7 summit in La Malbaie Canada
The group demonstrated solidarity in pledging to uphold the Iran nuclear deal, a major source of G7 contention after Trump's withdrawal last month.
In response, Trump posted on Twitter that Trudeau was "being so indignant" and said that both leaders were failing to make note of higher trade barriers they have leveled against US -made products. He also blamed former US President Barack Obama for Russia's move into that nation.
The group managed a common statement in which they agreed to disagree on some issues, only to have Trump disavow the document in a tweet after leaving the meeting.
It's revealing that he said "we should have Russian Federation at the negotiating table", because the G-7 meeting is not a negotiation. "We will stand by them and anyone who would depart from them... shows their incoherence and inconsistency".
Referring to the Mueller investigation, and the possibility it may result in criminal charges against him, Trump maintained he has "the absolute right to pardon myself", adding "but I'll never have to do it because I didn't do anything wrong". "We have opened both our country and our hearts to the world".
President Trump is heading up to Canada for the G-7 summit on Friday.
His remarks follow a report that White House officials were working towards setting up a meeting.
Putin said that during his last telephone conversation with the USA president, Trump "expressed his concern about the threat of a new round of the arms race". "In the interest of all". "It's a lucky number". The group, which welcomed new members India and Pakistan, as well as the presidents of Iran and Mongolia, pledged to increase cooperation on energy and agriculture and create more favourable conditions on trade and investment.More news: Nadal advances to 11th French Open final, will face Thiem for title