President Barack Obama says the nation will never forget the lives of those killed in the Sept. 11 attacks as the United States on Sunday commemorated the 15th anniversary of the attacks with a moment of silence observed in somber remembrance at Ground Zero in New York.
Obama said at a Pentagon memorial service that he is inspired by the resilience of the victims' families. He quoted Scripture: "Let not steadfast love and faithfulness forsake you. Write them on the table of your heart."
Obama also praised America's diversity and urged Americans not to let their enemies divide them. He called the day "difficult" but one that "reveals the love and faithfulness in your hearts and in the heart of our nation."
At the White House, Obama observed a moment of silence at 8:46 a.m. EDT — the time the first hijacked airplane hit the north tower of New York City's World Trade Center.
Presidential candidates Hillary Clinton and Donald Trump temporarily paused their bitter election campaign to attend the service with police and relatives of the victims at the September 11 memorial.
The Al-Qaeda attacks killed 2,753 people in New York, 184 at the Pentagon in Washington D.C and 40 on Flight 93 -- which had also been headed toward the US capital until passengers and crew staged a rebellion and the hijackers crashed it into a field in Pennsylvania.
Held at the September 11 memorial, the service also paused to mark the moment when the second plane hit the South Tower. Other moments of silence will take place when each tower fell, as well as the attack on the Pentagon and Flight 93.
In New York, police and relatives of those killed in the World Trade Center began the annual reading of the names of the victims at Ground Zero, now the site of the National 9/11 Memorial and Museum.
"September 11, 2001 touched every single NYer, but the terrorists did not prevail, because 15 years later we are strong, and we are unified," New York Mayor Bill de Blasio wrote on Twitter.