Biarritz, France (CNN) A sharp and sometimes bitter disagreement broke out between President Donald Trump and several G7 leaders over whether to allow Russia back into their club during a welcome dinner on Saturday, according to two diplomatic officials and a senior US official with knowledge of the exchange.

Trump, as he did in public over the course of the summit, ardently advocated for it, the officials said. As the leaders discussed issues like Iran and fires in the Amazon rainforest, Trump interjected and asked why Russia should not be included in the talks, given its size and role in global affairs.

That met sharp resistance from some of the leaders, principally German Chancellor Angela Merkel and British Prime Minister Boris Johnson. They argued Russia had grown more anti-democratic since it was ejected in 2014 for its incursion into Ukraine, disqualifying it from rejoining the G7.

The dispute amounted to one of the most heated moments of this weekend's G7. Afterward, Trump publicly insisted the gathering was marked by displays of unity and cooperation. While the leaders did hold amiable discussions throughout both the dinner and other sessions, the exchange on Russia was notable for the fiercely argued views on both sides, the officials said.

During the dinner, Trump argued repeatedly that his predecessor Barack Obama was to blame for ejecting Russia from the group, according to one of the diplomatic officials, echoing a view he has expressed publicly. He told reporters on Monday that Obama was "outsmarted" by Russian President Vladimir Putin during the invasion of Crimea.

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