UK Prime Minister Keir Starmer dismissed concerns about US President Joe Biden's age and mental fitness, praising his "leadership" after a bilateral meeting in Washington.

Starmer and Biden convened at the White House on Wednesday to address the Ukraine and Gaza wars, as well as trade and climate change.

In light of Biden's numerous gaffes, Starmer replied to a BBC inquiry about Biden's mental acuity, saying, “We had a really good bilateral [meeting] yesterday. We were billed at 45 minutes [but] we went on for the better part of an hour. We went through a huge number of issues at pace,” the prime minister said, adding that Biden “was actually [in] really good form, and absolutely across all the details.”

The prime minister said the conversation was productive, claiming that Biden had shown “incredible leadership.”

What's new with Biden? 

The day after, Biden made a notably awkward gaffe when he introduced Ukrainian leader Volodymyr Zelensky to an audience of supporters as “President Putin,” while NATO and EU leaders, as well as Zelensky himself, shared the stage with Biden.

Later on Thursday, the US leader made additional verbal slip-ups during a press conference, including confusing his vice president, Kamala Harris, with his main reelection rival, former President Donald Trump.

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Starmer dismissed concerns about Biden’s health on Thursday, saying he “deserves credit” for hosting the NATO summit in Washington. “I would urge everyone to look at the substance of what’s been achieved over these two days,” he said.

Could Biden be replaced?

Several Democratic Party politicians, major campaign donors, leading US media outlets, and Hollywood celebrities have urged Biden to end his reelection campaign and allow the party to select a replacement candidate. Despite these calls, Biden has refused to step down, asserting that he is the best candidate to defeat Trump in November.

On that note, Axios revealed on Thursday that Senate Majority Leader Chuck Schumer is discretely signaling donors that he's open to a Democratic presidential ticket that President Biden doesn't lead. That said, Schumer has been pro-Biden in public and the opposite in private.

For the past 12 days, Schumer has been gathering insights and recommendations from donors on the optimal path forward for the party, according to three individuals with knowledge of the situation.

The majority leader is among several prominent Democrats, such as former President Obama and former House Speaker Nancy Pelosi, who possess the political and personal influence to persuade Biden to step down. However, Biden can still resist, with delegates pledged to his support.

Read next: Latest in Biden's gaffes series: Europe was liberated from Nazis by US