British Prime Minister Sir Keir reiterated at the summit that the US president had achieved many things he could be proud of and that he had “understood every detail”.
On Friday, he added: “We had this meeting for two days and we had a very good outcome… and I think he deserves credit for that.”
Canadian Prime Minister Justin Trudeau said he was honoured and excited to work with President Biden.
According to the CBC, he said, “(Biden's) wealth of experience, thoughtfulness and unwavering commitment to the most important issues and challenges of our time are a compliment to the work we are all doing together.”
“I spoke to President Biden and I have no doubt that everything is fine,” said Polish President Andrzej Duda, who is known to be close to former President Trump, according to AFP.
Meanwhile, Finland's President Alexander Stubbs has combined his support for Mr Biden with concerns about the tone of the U.S. election.
“I have absolutely no concerns about the ability of the current US president to lead his country, to lead the fight for Ukraine, to lead NATO,” he said, according to AFP.
“What worries me is that the political climate in America right now is so toxic, so polarized, that there's not enough room for civilized, constructive debate.”
But not all NATO leaders have spoken out on behalf of President Biden.
Hungarian Prime Minister Viktor Orban reportedly made few comments to the press in Washington.
Instead, he left immediately after the summit for Trump's Florida retreat, Mar-a-Lago, where the two discussed the war in Ukraine.
“We discussed how to make peace,” Mr Orban said on social media. “The good news today is that he will solve the problem!”
