(CNN) - Maine's Republican Sen. Susan Collins criticized President Donald Trump for "alienating our closest allies" at the G7 summit, which she referred to as "an unfortunate incident."
"The President and his staff should not be alienating our closest allies, our longtime friends, our reliable allies and our biggest trading partners, in the case of the Canadians," Collins said on CNN's "Cuomo Prime Time" Tuesday evening.
Collins suggested that Trump's focus on his then-impending North Korea summit could have contributed to his actions at the G7 gathering.
"I think the President was not focused on the G7 meeting, that his mind was on the summit to come with North Korea," Collins told Chris Cuomo, "and I think that's very unfortunate because those allies are important."
Collins went on to call Trump's proposal to reinstate Russia to the G7 "a terrible idea." Russia was suspended from the group -- then known as the G8 -- in 2014 after the majority of member countries condemned Moscow's annexation of Crimea, which Russia continues to hold.
She seemed to criticize Trump for coming late to, and leaving early from, the G7 summit.
Additionally, Collins criticized the way Trump treated North Korean leader Kim Jong Un at their summit compared with his treatment of Canadian Prime Minister Justin Trudeau.
"Let me say, there is no comparison between Justin Trudeau and Chairman Kim," Collins said. "There's just no comparison at all."
Collins also pushed for a vote on an amendment by Tennessee's Republican Sen. Bob Corker that would roll back Trump's trade authority and give Congress the power to check the President's ability to impose tariffs on national security grounds, like the steel and aluminum ones he announced recently on US allies.
"Sen. Corker clearly deserves a vote on his amendment. It's a legitimate issue that he's raising," she said. "What Bob Corker is saying is that he wants to reassert the constitutional role of Congress in trade matters. He deserves a vote."