Trump and First Lady Melania Trump attended the solemn Pentagon ceremony, where the names of all 184 people killed in the attack on the building were read aloud.

A bell tolled after each name as officials and families remembered those who died when hijacked planes crashed into the Pentagon, the World Trade Center and a field in Shanksville, Pennsylvania.

“We will never, ever forget,” Trump said, recalling the determination that followed the attacks. “That’s why we fight today. We don’t have a choice.”

Trump invokes 9/11 unity

Trump also reflected on the sense of national solidarity that swept across the United States in the aftermath of the attacks.

“In those harrowing days after the attacks, we saw the authentic spirit of our nation,” he said, recalling how Americans came together in the wake of the tragedy.

The president also paid tribute to individual victims, recounting stories of some of those killed at the Pentagon.

The ceremony came amid nationwide commemorations marking a quarter-century since the attacks that transformed US foreign policy, national security and public life.

Trump, Hegseth link 9/11 to Iran conflict

Trump used the Pentagon ceremony to praise US service members involved in the ongoing conflict with Iran, saying they were working to prevent Tehran from acquiring a nuclear weapon.

“We salute the service members working right now to ensure the world's No. 1 sponsor of terror — the Islamic Republic of Iran — will never ever have a nuclear weapon,” Trump said.

Defence Secretary Pete Hegseth also connected the current conflict to the broader history of US-Iran tensions, citing Iran's actions and its relationship with militant groups.

Both Trump and Hegseth presented the Iran conflict as part of a broader national-security struggle involving threats that they said the US has faced for decades.

Trump returns to Pentagon for second year

Friday marked the second consecutive year Trump has observed the September 11 anniversary at the Pentagon.

The president had attended the Ground Zero commemoration in New York in 2024.

Vice President JD Vance joined this year's ceremony in New York alongside former presidents and other dignitaries, while other administration officials gathered in Shanksville to honour the passengers and crew of United Airlines Flight 93.

25 years later, 9/11 legacy endures

The anniversary ceremonies across New York, Washington and Pennsylvania reflected the continuing impact of the attacks on American society.

At Ground Zero, victims' relatives read the names of those killed, while a new moment of silence was observed for people who later died from illnesses linked to toxic dust exposure after the attacks.

The attacks led to sweeping changes in US security and foreign policy, including the creation of the Department of Homeland Security, expanded intelligence and surveillance powers and the US-led wars in Afghanistan and Iraq.

Their effects continue to shape American national-security policy 25 years later.