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

The third bell tolled at 9:37 a.m., which is the time American Airlines Flight 77 crashed into the Pentagon.

Prior to the start of the lower Manhattan ceremony, New York City Mayor Zohran Mamdani shook hands with former New York City Mayor Rudy Giuliani, who had publicly called on the city's first Muslim mayor not to attend.

The second moment of silence was held at 9:03 a.m., marking the moment United Airlines Flight 175 crashed into the World Trade Center's North Tower.

The annual reading of the victims' names is now underway at the ceremony at New York City's 9/11 Memorial & Museum.