The digs against his Republican rival come as the US president deflects criticism that his memory is hazy and he appears confused.

US President Joe Biden has joked about former President Donald Trump’s mental fitness during a speech at the Gridiron Club dinner, a Washington tradition that began in the 1880s.

“One candidate is too old and mentally unfit to be president. The other one is me,” Biden said on Saturday in front of more than 650 guests who included the Taoiseach of Ireland Leo Varadkar, Amazon founder and Washington Post owner Jeff Bezos, and TikTok CEO Shou Zi Chew, whose US business could be banned by Biden.

“Don’t tell him, he thinks he’s running against Barack Obama, that’s what he said,” said Biden, 81, who also quipped that he was staying up way past his bedtime.

Trump’s campaign did not respond, though the 77-year-old Republican leader has also questioned Biden’s mental capacity to be president. The Democratic leader has deflected ongoing criticism that his memory is hazy and he appears confused.

It was the first time Biden had attended the traditional dinner during his presidency, and comes as the 2024 election looms and the November rematch between Biden and Trump heats up.

Biden’s appearance at the dinner, in which politicians and journalists trade humorous barbs in a white-tie formal affair, was the first time a president has attended in person since Trump himself came in 2018.

Biden reinforced the importance of the press, which he said is not “the enemy of the people”, in stark contrast to previous remarks by Trump about the news media.

He also spoke about the war in Ukraine with Estonia’s Prime Minister Kaja Kallas, who attended Saturday’s dinner. “We will not bow down, they [Ukrainians] will not bow down and I will not bow down,” Biden said.

After his speech, Biden descended to the floor and took selfies with reporters and called one guest’s mother.

Michigan Governor Gretchen Whitmer, representing the Democratic Party at the event, also spoke, as well as Utah Governor Spencer Cox, representing the Republican Party.

Cox, 48, joked that he was announcing his candidacy for the presidency “in 2052, when I still will be younger than both President Biden and President Trump”.