Saddam Hussein's two sons were killed by US forces during a fierce gun battle in northern Iraq, it was confirmed last night.

Uday and Qusay Hussein were among four victims of a six-hour shoot-out after the American 101st Airborne Division raided a home in Mosul, said Lieutenant General Ricardo Sanchez, commander of coalition forces in Iraq.

"We are certain that Uday and Qusay were killed today," he told a news conference in Baghdad.

US troops stormed the house belonging to a cousin of Saddam after receiving "good intelligence" that his sons had recently been there.

When the troops approached the building, gunmen inside opened fire with small arms. The "suspects barricaded themselves in the house" and "resisted fiercely," said the general.

The raid took place in Mosul, a city 280 miles north of Baghdad, in an area largely controlled by Kurdish forces.

Confirmation of the deaths is expected to give a significant boost to US and British forces in Iraq who have faced strong resistance since major conflict in the country was officially declared over.

Analysts believe it would help remove the fear that the old regime could return, which prevents the population from coming forward with information about resistance fighters.

Retired US Army Major General Paul Valleley said it also might lead to the discovery of the former Iraqi dictator.

"One event can lead to the other, so hopefully, this will lead to determining in some way where Saddam may be," he said.

The pair were both aces in the 55 most wanted Iraqis pack of cards issued by the US.

Qusay, who was being groomed by Saddam as his successor, was number two on the US wanted list. Uday was number three and both men had £10m prices on their heads - dead or alive. There is a £15m reward for the discovery of Saddam.

Qusay ran much of Iraq's security apparatus, controlling several militias, internal security services and the military forces of the once-vaunted Republican Guard.

He was described as quiet and level, particularly compared to Uday, Saddam's eldest son, who had a liking for brutality, high living and sex.

Uday was in command of Saddam's Fedayeen, the paramilitary force that fought US troops during the war. Many of its survivors are thought to be part of the guerilla campaign in Iraq.

He also controlled propaganda in Saddam's Iraq.

According to some reports, Saddam has a third, younger son who kept out of public view. Saddam's three daughters also have kept a low profile.

Foreign Secretary Jack Straw said last night: "Uday and Qusay Hussein shared their father's responsibility for the many years of suffering by the Iraqi people.

"They had the opportunity to hand themselves in to justice and answer for their crimes.

"They refused to do this. It goes without saying that we would have much preferred this, but the news that Saddam's sons are no longer a threat to the security of Iraq will be a reassurance to the Iraqi people."