President Bush has said America will not relent in the war on terror until it is secure, in a speech marking the first anniversary of the 11 September attacks.

In a live televised address, Mr Bush said America had "entered a great struggle that tests our strength, and even more our resolve".

We have no intention of ignoring or appeasing history's latest gang of fanatics

President Bush

And in an apparent reference to Iraq, the president warned that America would not allow "any terrorist or tyrant" to threaten civilisation with weapons of mass destruction.

The speech from Ellis Island, with one of America's most symbolic landmarks, the Statue of Liberty, as a backdrop, followed a day of ceremonies and remembrance for the 3,025 people killed or missing as a result of last year's attacks.

Mr Bush said the past year had been one "of sorrow, of empty places, of newborn children who will never know their fathers here on earth".

	:	In pictures
The world remembers

But, he said, America had witnessed "the greatness" of airline passengers who fought back against hijackers and of rescuers "who rushed up flights of stairs towards peril".

'Determined enemies'

Mr Bush said that 11 September had shown that America had "determined enemies, and that we are not invulnerable to their attacks".

What our enemies have begun, we will finish

President Bush

But, he said, America would "not relent until justice is done and our nation is secure."

"What our enemies have begun, we will finish," he added.

The president urged the American people to be confident, vowing that "Americans will live as free people, not in fear, and never at the mercy of any foreign plot or power".

"We have no intention of ignoring or appeasing history's latest gang of fanatics trying to murder their way to power," he said.

Commemorations

Earlier, Mr Bush and his wife, Laura, met friends and relatives of the victims at the former site of the World Trade Center.

Bush visited all three crash sites

The couple flew into New York after leading tributes at the site of the attack on the Pentagon in Washington, and a field near Shanksville, Pennsylvania, where the fourth hijacked airliner was brought down.

In New York, the occasion was marked with a ceremony at Ground Zero, where the names of the victims of the attacks on the twin towers were read out, one by one, in a sombre roll-call.

As the sun set, world leaders joined Mr Bush for a memorial service at The Sphere - a damaged sculpture which stood in the World Trade Center plaza and is now housed in New York's Battery Park.

Flights diverted

New York Mayor Michael Bloomberg lit an eternal flame as candle-lit vigils got under way in each of New York's five boroughs.

Here in NYC it is very quiet, very serious and sombre. Also there is a great spirit of optimism, we all know NYC will come through this

Fiona, New York City

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He then handed candles to the United Nations Secretary General Kofi Annan, US Secretary of State Colin Powell and representatives of 91 other countries.

Earlier, the UN Security Council held a special commemorative session at which members called on all states to continue the fight against terrorism.

Two American planes on domestic flights were diverted on Wednesday because of security alerts.

A flight bound for Dallas was escorted by F-16 fighter aircraft back to Houston after passengers thought they saw someone with a weapon on board. It turned out be a comb.

In the other incident, a plane flying from Memphis to Las Vegas was diverted to Arkansas when the crew became concerned about a group of passengers who had apparently locked themselves in a lavatory.