President Joe Biden briefly donned a red “Trump 2024” hat during a visit to a Shanksville, Pennsylvania fire station, in what the White House described as a gesture of unity on the anniversary of the September 11 attacks.

“At the Shanksville Fire Station, @POTUS spoke about the country’s bipartisan unity after 9/11 and said we needed to get back to that,” White House senior deputy press secretary Andrew Bates posted on social media.

Bates said Biden gave a hat to a Trump supporter in the crowd as a friendly gesture. The supporter then asked Biden to put on a Trump cap in the name of bipartisanship, and the president went along, briefly wearing the red hat.

“As a gesture, he gave a hat to a Trump supporter, who then suggested that, in the same spirit, POTUS should wear the Trump cap. He briefly put it on,” Bates added.

Biden, who was in Shanksville, the rural area where United Airlines Flight 93 crashed into a field 23 years ago, wore the hat during a private meeting with community members and then took a picture with a group of children. The photo of the moment quickly went viral, particularly among Republicans.