However, the new Italian PM backed Trump's suggestion - saying it would be in everybody's interest
Most of the members of the G7 have rejected a call by Donald Trump to reinstate Russia into the group of industrialised nations.
The US, French, UK, German, Italian and Japanese leaders have joined Canadian Prime Minister Justin Trudeau in Quebec for the summit, along with senior EU officials Donald Tusk and Jean Claude Juncker.
Speaking ahead of the summit, Donald Trump told reporters: "Why are we having a meeting without Russia being in the meeting?".
He added that the country - which was kicked out of the group in 2014 when it annexed Crimea - should be at the negotiating table.
Responding to the call, German Chancellor Angela Merkel said: "[European leaders] are in agreement that a return of Russia to the G7 cannot happen unless substantial progress is made in terms of the problems with Ukraine."
Canadian Foreign Minister Chrystia Freeland suggested there were 'no grounds' for Russia being reinstated due to their "current behavior".
However, the new Italian Prime Minister Giuseppe Conte did back President Trump's call - saying that allowing Russia back in would be in everybody's interest.
During the first day of the summit yesterday, the G7 countries are said to have agreed to a "unified" response to hostile actions by Russia.
It followed the Salisbury nerve agent attack - which the UK and its allies have accused Russia of being behind - and alleged Russian efforts to interfere in the 2016 US election.
In a draft statement quoted by Reuters, the leaders said: "Foreign actors seek to undermine our democratic societies and institutions, our electoral processes, our sovereignty and our security."
British Prime Minister Theresa May noted: "Calling out malicious activity helps to end hostile states' false sense of impunity, demonstrates our awareness of their activity, and underlines our unwavering willingness to defend ourselves."
Trade is expected to be a major topic of discussion on day two of the summit, amid tensions between Donald Trump and the other countries over the recent steel and aluminum tariffs imposed by the US.
Fears of a trade war have led to concerns that the G7 leaders may not be able to agree to a final joint statement - but following a meeting with Justin Trudeau yesterday, President Trump suggested a statement would be agreed.
The US President is expected to leave the summit early, as preparations continue for his historic summit with North Korea's Kim Jong Un in Singapore on Tuesday.