The UK and Canada opposed Russia's return to the G7, widening the divide over US President Donald Trump's wish to join the country.
Trump said on Saturday that he would postpone the G7 summit scheduled for this month until September.
The president said the G7's "outdated group of countries" should be expanded to include other countries, including Russia.
On Sunday, Mr. Trump informed Russian President Vladimir Putin of his intention to invite him to the summit.
The White House said that "progress towards the convening of the G7" with Russia was among the topics raised by leaders in a phone call.
The G7 summit, which the United States is hosting this year, brings together leaders from Canada, France, Germany, Italy, Japan, and the United Kingdom to discuss issues of cooperation.
But Trump's invitation to Putin has drawn anger from the UK and Canada, whose leaders said on Sunday that they would not support the readmission of Russia to the group.
Russia was expelled from the group – formerly known as the G8 – in 2014 due to its annexation of Crimea.
"Russia has been excluded from the G7 after invading Crimea several years ago, and its disrespect and display of international rules and standards is why it remains outside the G7, and will continue to do so. 39; be, ”said Prime Minister of Canada Justin. Trudeau said at a press conference.
Earlier, a spokesperson for British Prime Minister Boris Johnson said he would veto any proposal to allow Russia to join the group.
Unless Russia stops its "aggressive and destabilizing activity", the United Kingdom will not support the readmission of the country to the group, said Johnson's spokesman.
"Russia has been removed from the G7 group of nations following its  the annexation of Crimea and we have not yet seen evidence of a change in behavior that would justify his readmission, "the spokesman told reporters.
Neither the British nor Canadian position precludes Mr. Putin's presence at the summit in the United States.
Although representatives of countries not members of the G7 have already attended the group's summits, the presence of Mr Putin could prove controversial.
In recent years, the UK has had an acrimonious relationship with Russia, which it has blamed for a nerve agent attack on a former Russian spy in Salisbury, England in 2018.
Despite opposition from other G7 members, Trump has repeatedly expressed support for Russia's return to the group.
At a G7 summit in 2018, Trump said he thought "it would be an asset to bring Russia back."
Announcing the delay in this year's G7 summit on Saturday, Trump echoed that sentiment.
He said he did not think the group "correctly represents what is going on in the world", suggesting that Russia, South Korea, Australia and India should be invited .
The leaders of South Korea and Australia have expressed interest in attending the summit in the United States.
Last week, Chancellor Angela Merkel rejected the President's invitation to attend a summit in person due to the coronavirus pandemic.
The G7 (or Group of Seven) is an organization made up of the seven largest so-called advanced economies in the world.
The leaders of these countries meet annually at summits to discuss global governance issues, including climate change, security and the economy.
The group sees itself as "a community of values", with freedom and human rights, democracy and the rule of law, and prosperity and sustainable development as key principles.