September 11 attacks: 25 years later and the evolving terrorism threat

The 25th anniversary of the September 11 terrorist attacks in the United States marks a significant milestone in global security history. The attacks, which resulted in nearly 3,000 deaths, involved the hijacking of four commercial aircraft, two of which struck the World Trade Center in New York and one which hit the Pentagon.

Experts note that while the nature of terrorism has evolved, the threat remains significant. Olli Ruohomäki, a visiting expert at the Institute of International Affairs, observes that the number of salafist-jihadist groups has increased from approximately 30 twenty-five years ago to over 80 today. While no single group currently possesses the same centralized capability as al-Qaeda did in 2001, cells from organizations like ISIS have found new platforms for activity, fueled in part by regional tensions in Gaza and conflicts involving Iran.

Security measures, particularly in aviation, have changed drastically since 2001, making the specific tactics used during the 9/11 attacks—such as hijacking aircraft to strike buildings—highly unlikely to be repeated due to enhanced cockpit security and airport surveillance.

Commemorative ceremonies are being held in New York and at the Pentagon. While political tensions have surfaced regarding the participation of certain officials in memorial services, several former U.S. presidents, including Joe Biden, Barack Obama, Bill Clinton, and George W. Bush, are expected to attend the ceremonies.