The world is safer today than in the aftermath of the September 11 attacks on the United States, with global terror groups weaker than 10 years ago, senior EU and NATO officials said Monday.

A decade after Al-Qaeda traumatised the United States, the terror network has lost its leader, Osama bin Laden, and proved irrelevant in the revolutions sweeping the Arab world, said EU counter-terrorism coordinator Gilles de Kerchove.

"The main finding is the real failure of the Al-Qaeda project," he said.

The once mighty group has been worn down by the NATO-led war in Afghanistan, which served as its safe haven prior to 9/11, and reinforced international cooperation, de Kerchove said.

"Today an attack of the scale and sophistication of 9/11 is no longer possible," he told a news conference. "Does it mean that we're completely out of the threat? Probably not."

He added: "Are we safer today than before? I can say yes."

De Kerchove stressed that the world still faced terror threats, as the deadly shooting and bombing rampage by a Norwegian right-wing extremist showed this summer in Norway.

Terrorism has also evolved into a more complex and diversified menace, with Al-Qaeda franchises operating in Africa and the Arabian peninsula, he said.

At a separate briefing, NATO Secretary General Anders Fogh Rasmussen noted that 9/11 prompted the military alliance to invoke its mutual defence clause for the first time in its history and deploy troops to Afghanistan.

Many countries have also introduced "heavy control measures" to protect their populations, seeking a balance between safeguarding "the freedoms we believe in" and ensuring people "can continue to lead their lives in security and safety," he said.

"Today we have a safer world than we had 10 years ago," Rasmussen said. "The overall picture is that international terror networks have been significantly degraded since 2001."