Since 2003, the ceremony at the Los Angeles Fire Department training facility has marked the anniversary of the 9/11 attacks.
LAFD Interim Chief Ronnie Villanueva, Mayor Karen Bass, County Fire Chief Anthony Marrone, LAPD Chief Jim McDonnell, Sheriff Robert Luna and other elected officials attended the ceremony.
"On this day, 24 years ago, the unimaginable occurred. Each of us recalls where we were the day the news broke here in Los Angeles, we felt a unique shock and grief that day," Bass said.
The mayor emphasized that they also witnessed communities together in the wake of tragedy. Members of the LAFD, alongside other first responders across the nation, rose to serve the country hours after the attack.
"Members of the LAFD Urban Search and Rescue Task Force headed to Ground Zero with one mission in mind: To serve," Bass said.
She reiterated that 9/11 is a day to honor the lives lost, and also those who protect our cities and our country.
Villanueva echoed the mayor's sentiments, adding that "We promised then and we promised now that we will never forget that morning between the World Trade Center, the Pentagon and the heroic passengers of flight 93.
"Nearly 3,000 innocent lives were lost. Families were shattered. Communities were broken and the nation was shaken," Villanueva said. "Yet in that darkness, we also saw the extraordinary courage."
"From 24 years ago to today, the words and thoughts of those who were there continue to resonate with us," he added.
Events were scheduled throughout the region to honor victims and first responders, including at the L.A. city fire training facility, where more than 1,000 volunteers packed about 400,000 meals to people in need.
City News Service contributed to this report.