WASHINGTON (AFP) - Five years after US special forces killed Osama bin Laden, President Barack Obama says he hopes that in his last moments the terror mastermind realized Americans had not forgotten about 9/11.

In an interview with CNN broadcast on Monday (May 2), Obama marked the anniversary of what many see as one of his presidency's greatest achievements: ending the long hunt for the illusive Saudi-born Al-Qaeda boss.

US special forces killed bin Laden in Pakistan on May 2, 2011.

"Hopefully, at that moment, he understood that the American people hadn't forgotten the some 3,000 people who he killed," Obama said.

Obama leaves office in January, with Al-Qaeda significantly diminished by drone strikes and somewhat eclipsed by its offshoot, the so-called Islamic State group.