The US president warns that terror groups will target the US again and urges vigilance as America marks the anniversary of the September 11 attacks.
US President Barack Obama has said the US is stronger and al-Qaeda is in decline, a decade after the September 11 attacks.
Mr Obama said the Islamist terror network’s strength has been sapped by relentless US efforts in the decade since the 9/11 attacks on New York, Washington and Pennsylvania killed nearly 3,000 people.
In his weekly radio and internet address, the president said: “Thanks to the tireless efforts of our military personnel and our intelligence, law enforcement and homeland security professionals, there should be no doubt: today, America is stronger and al-Qaeda is on the path to defeat.
New York police mounted a show of strength on Friday, including checkpoints that held up traffic in response to intelligence about a car or truck bomb plot linked to the anniversary.
Read more: Channel 4 News’s Washington Correspondent Matt Frei blogs from New York
Mr Obama said terror groups would continue to target the United States, saying: “Yes we face a determined foe, and make no mistake – they will keep trying to hit us again. But as we are showing again this weekend, we remain vigilant.”
They will keep trying to hit us again. But as we are showing again this weekend, we remain vigilant. Barack Obama
Obama will travel to all three sites on Sunday where hijackers turned planes into missiles, bringing down the twin towers of the World Trade Center in New York, hitting the Pentagon in Virginia and crashing into a Pennsylvania field.
The attacks sparked US-led wars in Afghanistan and Iraq, the second of which Obama opposed.
Former Prime Minister Tony Blair, who sent British troops into both countries, insisted “significant blows” had been struck in the war on terror but admitted “it’s not over”.
Speaking from his London home on the eve of 9/11, he defended the actions he took in the wake of the atrocity and said it was “deeply naive” to believe the response of the West had radicalised extremist Muslim factions.
He told the BBC: “It is not because of something we are doing to them. They believe in what they believe in because they believe their religion compels them to believe in it.
“I think it will take a generation, but the way to defeat this ideology ultimately is by a better idea, and we have it, which is a way of life based on openness, democracy, freedom and the rule of law.”