As the world marks the seventh anniversary of the 9/11 attacks America prepares to switch tactics in its hunt for Bin Laden

The sombre date comes as the US military concedes it is not winning the battle against an increasingly deadly insurgency in Afghanistan.

In a rare move President Bush was roundly criticised by American military and intelligence chiefs hunting the al-Qaeda leader for ignoring Afghanistan while he launched the war in Iraq.

Anniversary: The "Tribute in Light" illuminates the sky over the World Trade Centre site

World tributes: Students light candles to mark the seventh anniversary of 9/11 at a school in the northeastern Indian city of Siliguri

But the White House was defensive. "This isn't the movies. We don't have super powers," said a spokeswoman.

She added that 9/11 was the first thing the President thought about in the morning when he got up, and the last thing he thought about in the evening when he went to bed.

Senior US leaders point out there has been no confirmed sighting of bin Laden since he narrowly escaped from the CIA after the battle of Tora Bora in Afghanistan in December, 2001, three months after the attacks on New York and the Pentagon.

CIA and special forces bosses said the US has so alienated tribesmen along the Afghan-Pakistan border who are believed to be protecting 51-year-old bin Laden and his men that they have abandoned hopes of getting HUMINT – human intelligence reports from informants – and are switching to raids by unmanned Predator spy planes.

The Predators' deadly Hellfire missiles have been used 11 times so far this year – more than three times as much as in 2007.

New York tributes: People look at flags on which are printed the names of all the 9/11 victims at a memorial erected this morning in Manhattan's Battery Park near Ground Zero

Terrified New Yorkers run from the devastation in the moments after the attacks in 2001 as the towers burn in the background

In the last month they have killed two top al-Qaeda leaders. Local tribesmen had refused to target the al-Qaeda men despite $5 million bounties on their heads.

John Brennan, a former deputy executive director of the CIA and a former chief of the US National Counterterrorism Centre told the Washington Post: "Iraq was a fundamental wrong turn. That was the most strategically negative action that was taken."

The CIA shut down Alec Station, its special unit dedicated to tracking bin Laden late in 2005, two years after the invasion of Iraq, because it was getting nowhere.

Intelligence chiefs yesterday said they are convinced the Saudi-born terror leader is still hiding in the Pakistan mountains bordering Afghanistan.

He is believed to regularly wear disguises. He also avoids phones and emails, relying on human couriers to pass messages.

attack site: The Pentagon Memorial, dedicated in honor of the victims of the Sept. 11, 2001 attack on the Washington building

At large: The hunt is ongoing for Osama bin Laden

This morning it was revealed that President Bush secretly approved orders to allow American special forces to carry out ground assaults inside Pakistan without the prior approval of the Pakistani government.

The classified orders signal a watershed for the Bush administration after nearly seven years of trying to work with Pakistan to combat the Taliban and Al Qaeda.

It comes after months of high-level stalemate about how to challenge the militants’ increasingly secure base in Pakistan’s tribal areas.

U.S. officials say that they will notify Pakistan when they conduct limited ground attacks but that they will not ask for its permission.

The orders reflect concern about safe havens for al-Qaeda and the Taliban inside Pakistan, as well as an American view that Pakistan lacks the will and ability to combat militants.

They also highlight distrust of the Pakistani military and intelligence agencies and a belief that some American operations had been compromised once Pakistanis were advised of the details.

President Bush and first lady Laura Bush will mark the anniversary of the Sept 11 attacks during a moment of silence on the South Lawn.

It will happen at 8.46am New York time - the exact moment in 2001 when terrorists slammed the first of two jetliners into the World Trade Center in New York.

The president also will attend a ceremony at the Pentagon for the dedication of a memorial for the people killed there.

'Today is obviously a very sober anniversary for Americans," Dana Perino, the White House spokeswoman said.

'The president thinks about 9/11 every single day when he wakes up and before he goes to bed. This is what he's concerned about. He's always been concerned about another attack on our country. Thankfully, we haven't had one.'

• The only permanent memorial to those who died in the 9/11 attacks was being unveiled today at the spot where American Airlines Flight 77 hit the Pentagon. The £11 million memorial is made up of 184 benches, each bearing the name of one of the victims who died there. Memorials at the World Trade Centre and in the Pennsylvania field where battling passengers brought down their plane have been delayed by arguments and cost cutting.