Americans have looked back on the September 11 terror attacks with solemn ceremonies and a presidential tribute to "the moment when America fought back."
Thousands of survivors, victims' relatives, rescuers and others gathered on a misty Tuesday at the memorial plaza in New York where the World Trade Centre's twin towers once stood.
US President Donald Trump and Vice President Mike Pence headed to the two other places where hijacked planes crashed on September 11, 2001: a Pennsylvania field and the Pentagon.
Seventeen years after losing her husband, Margie Miller was among those who went to the New York City ceremony.
"To me, he is here. This is my holy place," she said before the hours-long reading of the names of the nearly 3000 dead, including her husband, Joel Miller.
The president and first lady Melania Trump joined an observance at the September 11 memorial in a field near Shanksville, Pennsylvania.
The field was where one of the jetliners fell to the ground after 40 passengers and crew members realised hijackers had taken control and tried to storm the cockpit.
Calling it "the moment when America fought back," Trump said the fallen "took control of their destiny and changed the course of history."
They "joined the immortal ranks of American heroes," he said.
Pence recalled the heroism of service members and civilians who repeatedly went back into the Pentagon to rescue survivors.
The terrorists "hoped to break our spirit, and they failed," he said.
The September 11 commemorations are by now familiar rituals, centred on reading the names of the dead. But each year at ground zero, victims' relatives infuse the ceremony with personal messages of remembrance, inspiration and concern.
Nicholas Haros Jr, who lost his 76-year-old mother Frances, pleaded for officials to stop invoking September 11 for political purposes
"Please stop using the bones and ashes of our loved ones as props in your political theatre," he said.
"Their lives, sacrifices and deaths are worth so much more. Let's not trivialise them."
