BAGHDAD, Dec 21: Nineteen US military personnel were among the 22 people killed on Tuesday when a blast ripped through a dining hall at a US base in the northern Iraqi city of Mosul, a US army spokesman said.

"Twenty-two people were killed in action, 19 of them being US military personnel," Captain Brian Lucas told AFP, without specifying how many of them were soldiers. Another three military personnel, whose nationality was unknown, also died in the attack. Another 57 people were wounded, Lucas added.

The attack came as British Prime Minister Tony Blair made a surprise visit to Baghdad and French officials confirmed that two journalists seized by militants on Aug 20 had been released.

Mr Blair vowed the "war on insurgents" would be won and elections would go ahead on Jan 30. As he left, mortars fell on Baghdad's Green Zone compound, as they do almost daily. There appeared to be no casualties.

The Mosul strike came at noon when many soldiers at Forward Operating Base Marez, a huge camp built around the northern city's airfield, would have been eating lunch. The tented dining hall can seat hundreds of soldiers at a time.

Major General Carter Ham, the commander of the 8,000 US troops based in Mosul, said the dead included American soldiers, US and foreign contractors and members of the Iraqi army.

"More than 20 have been killed and more than 60 people have been wounded," he said, adding there was a single explosion. Mosul has seen a surge in attacks over the past six weeks, since US forces launched an offensive against guerrillas in Fallujah, an assault designed to break the back of the guerrilla movement before next month's election.

In the bloodiest previous single incident for US troops in Iraq, two Black Hawk helicopters crashed in Mosul in November last year, killing 17 soldiers. At the start of the invasion in March last year, 29 soldiers were killed in a fierce day of fighting.

Iraqi militant group Ansar al Sunna claimed responsibility for the Mosul attack. Responding to the assault, the White House vowed that the "enemies of freedom" would be defeated. On Monday, President George Bush warned that Iraqi bombers were having an impact.

OIL PIPELINES SET ABLAZE: Saboteurs have set a complex of oil pipelines ablaze in northern Iraq, but exports on the line had already been halted by a separate attack at the weekend.