9/11 ceremony live updates: Families gather at WTC, Pentagon, Shanksville to mark 25 years

For the first time, the 9/11 Memorial & Museum added a seventh moment of silence at this year's ceremony to honor those who have died of illnesses related to their time at or near the World Trade Center site.

For the past 24 years, there have been six moments of silence: two to mark the times when the planes struck the World Trade Center towers; one to mark when a plane struck the Pentagon; one to mark when a plane crashed in Shanksville, Pennsylvania; and the two times the World Trade Center towers collapsed. Each moment of silence is followed by a bell toll.

This new, seventh moment of silence was observed at the conclusion of the reading of the names and will be a permanent part of the annual ceremony.

More than 9,000 people have now died from 9/11-related illnesses, approximately three times the number killed on Sept. 11, 2001, according to the World Trade Center Health Program.

Hundreds of people gathered in Shanksville, Pennsylvania, to mark the 25th anniversary of United Flight 93's crash.

The family members of the 40 passengers and crew who were killed read their names, accompanied by bells.

The color guard folded a U.S. flag and placed it on a giant rock near the edge of a grove of hemlocks. That rock is where some of the very last pieces of Flight 93 came to rest.

Cheers erupted during the Manhattan ceremony after Terry Strada, who lost her husband Tom on 9/11, condemned Saudi Arabia for its alleged role in the terrorist attacks.

"You are missed more with every day that passes, but how can it be 25 years and we have no justice for the role that Saudi Arabia played in your murder," she said of her husband.

As ABC News reported last week, a coalition of victims' families are suing the Saudi government over its alleged role and have continued to pursue evidence they say points to deep Saudi complicity. The Saudis deny that claim and are fighting the suit in court.

The Saudis have repeatedly denied having any role in facilitating the attacks and replied in court that they remain "an ally of the United States (and) a sworn enemy of Al Qaeda."

White House spokesperson Anna Kelly told ABC News last week that, "President Trump is leading the most transparent administration in history, and his team is working diligently to identify records that are responsive to these families' request."

Strada called out "administration after administration" for choosing "to protect the Saudis instead of standing with the 9/11 families."

"President Trump can still change that. Tell the Saudis to stop lying," she said.

Strada finished her speech by talking directly to Vice President JD Vance, who was in attendance, and told him to carry that message to the president.

"Stand with survivors, stand with Americans," she said. "As my husband Tom would have said, that is always the right thing to do. God bless all of us. God bless America."

The sixth moment of silence was held at 10:28 a.m., to mark the moment the World Trade Center's North Tower collapsed, nearly 30 minutes after the South Tower fell.