Americans are marking 24 years since the Sept. 11, 2001, attacks on Thursday with solemn ceremonies, volunteer work and other tributes honoring the victims.
Many loved ones of the nearly 3,000 people who were killed joined dignitaries and politicians at commemorations Thursday in New York, at the Pentagon and in Shanksville, Pennsylvania.
President donald Trump and first lady Melania Trump attended the service at the Pentagon in Virginia, where 184 service members and civilians were killed when hijackers steered a jetliner into the headquarters of the U.S. military.
"On that fateful day, savage monsters attacked the very symbols of our civilization. Yet here in Virginia and in New York and in the skies over Pennsylvania, Americans did not hesitate," Trump said in his remarks, which included anecdotes about victims of the attack. "They stood on their feet, and they showed the world that we will never yield, we will never bend, we will never give up, and our great American flag will never, ever fail."
Trump warned that if the United States is attacked, "we will hunt you down."
"We will crush you without mercy, and we will triumph without question. That’s why we named the former department of defense the department of War," he said, referring to the department's new secondary name. "It will be different. We won the First World War. We won the Second World War. We won everything before that and in between. And then we decided to change the game.”
At ground zero in lower Manhattan, the names of the attack victims were read aloud by family members and loved ones, including denise Matuza, Jennifer Nilsen and Michelle Pizzo. They boarded a bus from Staten Island for lower Manhattan on Thursday morning — each wearing T-shirts emblazoned with the names and faces of their husbands, who died in the attack.
“Even 24 years later, it’s heart-wrenching,” said Nilsen, whose husband, Troy Nilsen, worked at Cantor Fitzgerald on the 103rd floor of the World Trade Center. “It feels the same way every year.”
Others choose to mark the day at more intimate gatherings.
James Lynch, who lost his father, Robert Lynch, in the World Trade Center attack, said he and his family will attend a ceremony near their hometown in New Jersey before they spend the day at the beach.
“It’s one of those things where any kind of grief, I don’t think it ever goes away,” Lynch said as he, his partner and his mother joined thousands of volunteers preparing meals for the needy at a 9/11 charity event in Manhattan the day before the anniversary. “Finding the joy in that grief, I think, has been a huge part of my growth with this.”

The remembrances are being held during a time of increased political tensions. The 9/11 anniversary, often promoted as a day of national unity, comes a day after conservative activist Charlie Kirk was shot and killed as he was speaking at a college in Utah.
Kirk’s killing was expected to prompt additional security measures around the 9/11 anniversary ceremony at the World Trade Center site, authorities said.
Vice President Jd Vance arrived in Utah on Thursday helped carry Kirk's casket to Air Force Two for the flight to Phoenix.
Moments of silence marked the exact times when hijacked planes struck the World Trade Center’s iconic twin towers, as well as when the skyscrapers fell.

And in a rural field near Shanksville, a similar ceremony marked by moments of silence, the reading of names and the laying of wreaths will honor the victims of Flight 93, the hijacked plane that crashed after crew members and passengers tried to storm the cockpit. Veterans Affairs Secretary doug Collins attended that service.
Trump traveled to New York later on Thursday to attend the baseball game between the New York Yankees and the detroit Tigers that included a pregame ceremony commemorating 9/11. during the national anthem he was met with a mix of boos and chants of "USA" when he was displayed on the Jumbotron.
People across the country are marking the anniversary with service projects and charity works as part of a national day of service, with volunteers taking part in food and clothing drives, park and neighborhood cleanups, blood banks and other community events.
In all, the attacks by Al Qaeda militants killed 2,977 people, including many financial workers at the World Trade Center and firefighters and police officers who had rushed to the burning buildings trying to save lives.

The attacks reverberated globally and altered the course of U.S. policy, both domestically and overseas. It led to the “Global War on Terrorism” and the U.S.-led invasions of Afghanistan and Iraq and related conflicts that killed hundreds of thousands of troops and civilians.
While the hijackers died in the attacks, the U.S. government has struggled to conclude its long-running legal case against the man accused of masterminding the plot, Khalid Sheikh Mohammed, the former Qaeda leader who was arrested in Pakistan in 2003 and later taken to a U.S. military base at Guantánamo Bay, Cuba, but has never received a trial.
The anniversary ceremony in New York was taking place at the National Sept. 11 memorial and Museum, where two memorial pools ringed by waterfalls and parapets inscribed with the names of the dead mark the spots where the twin towers once stood.
The Trump administration has been contemplating ways the federal government might take control of the memorial plaza and its underground museum, which are now run by a public charity chaired by former New York Mayor Michael Bloomberg, a frequent Trump critic. Trump has spoken of possibly making the site a national monument.
In the years since the attacks, the U.S. government has spent billions of dollars providing health care and compensation to tens of thousands of people who were exposed to the toxic dust that billowed over parts of Manhattan when the twin towers collapsed. More than 140,000 people are still enrolled in monitoring programs intended to identify those with health conditions that could be linked to hazardous materials in the soot.