Published: 2017-09-12 00:11:24 BdST
Trump and First Lady Melania Trump walked onto the South Lawn and stood as bells tolled for the first 9/11 anniversary of Trump's presidency. They then bowed their heads and stood silently before placing their hands on their hearts as a bugler played "Taps."
Thousands were gathering nationwide to mark the deadliest attack on US soil.
Trump and the First Lady will later attend a memorial ceremony at the Pentagon, the Washington Post reported. Defence Secretary James Mattis and General Joseph Dunford, Chairman of the Joint Chiefs of Staff, are also due to host a private ceremony at the Pentagon for relatives of the victims.
Nearly 3,000 people died after hijackers crashed planes into New York's World Trade Centre, the Pentagon and a rural Pennsylvania field in 2001. The attacks were directed by Al Qeada leader Osama bin Laden.
The White House commemoration took place at the same time relatives of 9/11 victims, survivors, rescuers and others gathered at New York's 9/11 memorial on Monday at 08.46 (local time) to mark the exact time the first plane struck the World Trade Centre's North Tower.
The names of those killed were being read aloud at the 9/11 Memorial and Museum as bells rang out in memory of the dead.
Vice President Mike Pence travelled to Shanksville, Pennsylvania, where one of the four hijacked jetliners crashed after passengers overpowered the hijackers. He is scheduled to speak later at the rural site of the crash. He and his wife will tour the Flight 93 National Memorial nearby.