WATCH: Biden wears Trump hat at Pennsylvania event

President Joe Biden briefly donnes a red Trump 2024 hat during a 9/11 commemoration ceremony in Shanksville, Pennsylvania, on Wednesday, in what the White House described as a gesture of bipartisan unity.

The event marked the 23rd anniversary of the September 11 terror attacks, where United Flight 93 had crashed after passengers fought the hijackers.

Biden’s action occurred during a conversation with firefighters at the Shanksville Fire Station. He was handed the hat by a Trump supporter after giving his own hat to the individual.

The brief moment, captured on camera, quickly gained attention online, with Republicans seizing the opportunity to criticise the 81-year-old president’s mental acuity. Some claimed the president was unaware of what the hat represented.

The Trump War Room social media account posted a video of Biden wearing the hat, commenting that it was a response to Vice President Kamala Harris's debate performance the previous night. The post read: "Kamala did so bad in last night's debate, Joe Biden put on a Trump hat."

In response to the growing speculation, White House spokesperson Andrew Bates clarified the situation, stating that Biden’s intention was to promote the spirit of unity that had defined the country in the aftermath of the 9/11 attacks.

“At the Shanksville Fire Station, President Joe Biden spoke about the country’s bipartisan unity after 9/11 and said we needed to get back to that,” Bates posted on X, formerly known as Twitter. “As a gesture, he gave a hat to a Trump supporter, who then said POTUS should put on his Trump cap. He briefly wore it.”

The moment came the day after Trump and Harris clashed in a heated debate, and Biden’s presence in Shanksville, a region that overwhelmingly supported Trump in the 2020 election, was seen as politically significant.

The broader Somerset County, where Shanksville is located, voted 78% in favour of Trump over Biden in the last presidential election.

Bates’s statement aimed to underscore Biden’s commitment to restoring unity in a politically divided nation while others viewed it as a rare moment of bipartisan goodwill.

Biden, Harris, and Trump all participated in various 9/11 memorial services throughout the day, reflecting on the lives lost during the attacks.