In what amounts to a thinly-veilled rebuke of US President Donald Trump, leaders of the Group of Seven have issued a stinging warning to Vladimir Putin that Russia will face additional sanctions if it doesn’t stop covert meddling in other nations’ affairs.

Mr Trump stunned the summit when he called for Russia to rejoin the G7 nations, which expelled it in 2014 after Moscow’s seizure of the Crimea.

“We urge Russia to cease its destabilising behaviour, to undermine democratic systems and its support of the Syrian regime,” the leaders said in a statement at the end of their two-day meeting in La Malbaie, Quebec.

The G7 leaders condemned an attack in Salisbury in Britain on a former Russian spy using a Russian-made military grade nerve agent, saying it was highly likely Moscow was responsible because there was no other plausible explanation. Russia denies having anything to do with the attack.

The G7 leaders made a commitment on Friday, without naming Russia, to share information between themselves and work with internet service providers and social media companies to thwart foreign meddling in elections.

The Kremlin has denied allegations by the United States and some European countries that Russia interfered in their elections.

Earlier on Saturday, Trump told a news conference the issue of Russia’s return to the group was discussed. Russia was a member of the then G8 until it was expelled for annexing Crimea in 2014.

“I think it would be an asset to have Russia back in. I think it would be good for the world. I think it would be good for Russia. I think it would be good for the United States. I think it would be good for all of the countries of the current G7,” Trump said.

Italy’s new Prime Minister Giuseppe Conti was the only voice to back Mr Trump’s call

But the final communique struck a different note, saying sanctions would continue as long as Moscow failed to meet its obligations in Ukraine under the Minsk accord it signed, and could even be stepped up.

“We reiterate our condemnation of the illegal annexation of Crimea and reaffirm our enduring support for Ukrainian sovereignty, independence and territorial integrity within its internationally recognised borders,” the G7 statement said.

French President Emmanuel Macron said he would welcome his Russian counterpart Vladimir Putin at the next G7 summit to be held in France next year, but only if Russia delivered on its Minsk agreement commitments.

-with AAP