Critics say the Trump administrations cuts to CDC staff will negatively affect a health fund for 9/11 first responders.

Sixteen probationary staff members at the World Trade Center Health Program have been fired as part of the layoffs at the Centers for Disease Control and Prevention. ABC News’ Aaron Katersky reports.

The Biden administration succeeded in halting a plea hearing for alleged 9/11 mastermind Khalid Sheikh Mohammed.

Acting Secret Service Director Ronald Rowe and Republican Texas Rep. Pat Fallon got into a screaming match Thursday at a House hearing on the assassination attempt against Donald Trump.

The two candidates met again at the Sept. 11 memorial as the Harris campaign tried to capitalize on the debate with new ads and the Trump campaign tried to contain the damage.

Relatives gathered in downtown Manhattan Wednesday to read the names of those who died in the 2001 terrorist attacks.

ABC News chief global affairs correspondent Martha Raddatz sits down with Lt. Gen. Marc Sasseville to discuss his mission to intercept a hijacked flight on 9/11.

Vice President Kamala Harris and former President Donald Trump shook hands again Wednesday morning as they arrived at the 9/11 anniversary ceremony in downtown Manhattan.

Feal was a demolition supervisor at Ground Zero when a falling steel beam landed on his foot, requiring partial amputation.

Vice President Kamala Harris and former President Donald Trump shook hands again Wednesday morning as they arrived at the 9/11 anniversary ceremony in downtown Manhattan.

To honor the victims of the 9/11 attacks, President Joe Biden, Vice President Kamala Harris and former President Donald Trump will attend memorial ceremonies.

Memorial events will take place throughout the day remembering the thousands who lost their lives on that fateful day.

While investigators worked to identify and apprehend the 9/11 perpetrators, Osama bin Laden was committed to assassinating the U.S. president.

Twenty-three years after Sept. 11, 2001, illnesses linked to the World Trade Center attack have now killed more FDNY members than were killed on the day itself.

Twenty-three years after Sept. 11, 2001, illnesses linked to the World Trade Center attack have now killed more FDNY members than were killed on the day itself.

Defense Secretary Lloyd Austin revokes plea deal for alleged 9/11 mastermind Khalid Sheikh Mohammed and two others.

Reversing the plea deal for the accused plotters of the 9/11 attack, Secretary of Defense Lloyd Austin has revoked the agreement with the three suspects, putting the death penalty back on the table.

Defense Secretary Lloyd Austin revoked the plea deal bringing the death penalty back on the table for the alleged mastermind of the 9/11 terror attacks.

Three of the five 9/11 defendants at Guantanamo have reached a plea agreement with prosecutors, the Department of Defense announced Wednesday.

Three men accused of plotting the 9/11 terrorist attacks reached a plea agreement with prosecutors. Patrick White, the cousin of Louis Nacke II, a passenger aboard United 93, reacts.

Khalid Sheikh Mohammed, Walid Bin Attash and Mustafa Al Hawsawi reached a deal with military prosecutors to plead guilty to conspiracy and murder charges in exchange for life sentences.

The alleged mastermind behind the attacks and two other defendants have accepted a plea deal to avoid the death penalty. ABC News’ Andrea Fujii explains why some families of 9/11 victims are outraged.

Three of the five 9/11 defendants at Guantanamo Bay, including alleged mastermind Khalid Sheikh Mohammed, have reached a plea agreement with prosecutors, the Pentagon announced on Wednesday.

Ron DeSantis attended a 9/11 commemoration ceremony at ground zero in New York City on Monday, appearing with more than a dozen people who lost family on Sep. 11

Lt. Gen. Marc Sasseville speaks with Martha Raddatz about retiring from the from the U.S. Air Force and reflects on the moment he was asked to stop hijacked Flight 93.

ABC News’ @DannyNewTV examines the life of the 9/11 firefighter who stood beside President Bush at Ground Zero.

Firefighter Bob Beckwith, remembered for standing with President George W. Bush in an iconic photo at the World Trade Center site in the days after 9/11, has died.

Bob Beckwith, a retired FDNY firefighter who suited up and ran to help others at Ground Zero, passed away, the Uniformed Firefighters Association said.

The medical examiner's office announced Thursday it has positively identified a 9/11 victim's remains.

There have been 343 FDNY members who have died from 9/11-related illnesses, matching the number of the department's members who were killed in the attack, officials said.

The two rainbows appeared just after a storm passed through New York state.

The Tribute in Light illuminates the New York City skyline in memory of those lost on Sept. 11, 2001.

America marked 22 years since the terrorist attacks at the Pentagon, Pennsylvania and at ground zero.

Republican presidential candidate Vivek Ramaswamy commemorated the 22nd anniversary of the Sept. 11 terrorist attacks after he got criticized for past comments over them.

Former VP Mike Pence said Biden should have been in New York or at the Pentagon.

Families, survivors and others gathered at the World Trade Center, Pentagon and Pennsylvania to mark the somber anniversary.

President Joe Biden lands in Anchorage, Alaska, after the G20 summit to give his remembrance for the 22-year anniversary of the 9/11 attacks.

The remains of two more victims were identified last week as the nation remembers the attacks 22 years later. ABC News’ Derricke Dennis reports.

The names of the victims were read aloud, and moments of silence were held in New York as people honored the nearly 3,000 killed on Sept. 11, 2001.

The country reflects on the nearly 3,000 people who died at the Twin Towers, the Pentagon and in Shanksville, Pennsylvania, on Sept. 11, 2001, in the deadliest terror attack on U.S. soil.

Twenty-two years after the Sept. 11, 2001, terrorist attacks, the New York City's Office of the Chief Medical Examiner has positively identified two more victims.

The New York City Fire Department has added 43 new names to its World Trade Center Memorial Wall.

A moment of silence is observed to recognize the 9/11 terror attacks that took place in 2001.

Luke Laidley, a 9/11 survivor and dad of three, died on July 4 after jumping into Lake Michigan to help kids struggling in the water.

George Santos has invited a former ground zero volunteer firefighter Michael Weinstock to President Joe Biden's State of the Union address on Tuesday

The National Archives disclosed declassified notes from a 2004 interview.

A New York City paramedic who responded to the terrorist attacks on Sept. 11, 2001, will be laid to rest on Wednesday, six days after she was stabbed to death.

Twenty-one years after the Sept. 11 attacks, forensic scientists are still hard at work identifying remains found at Ground Zero.

A former MLB pitcher who retired and became a Port Authority police officer died in a car accident on his way to a Sept. 11 memorial ceremony on Sunday in New York City.

Families, friends and others attended somber ceremonies on Sept. 11 to honor those who lost their lives 21 years ago.