Mosul blast 'was suicide bombing'

General Myers said the base "is not unsecure"

An explosion that killed 22 people at a US military base in the Iraqi city of Mosul was probably the work of a suicide bomber, the Pentagon has said.

Gen Richard Myers, chairman of the US Joint Chiefs of Staff, told reporters "an improvised explosive device worn by an attacker" was the most likely cause.

He said further inquiries - in which the FBI is involved - would ask how an attacker gained access to the base.

Part of Mosul is under curfew after the blast, which hit a packed dining hall.

The explosion killed 22 people, including 13 US troops, five US civilian contractors, and four Iraqis.

We have had a suicide bomber apparently strap something to his body... and go into a dining hall Gen Richard Myers Chairman, US Joint Chiefs of Staff

Gen Myers did not say what evidence had led investigators to favour the suicide attack theory.

Initial reports said the explosion had been caused by a rocket or mortar.

On Tuesday, President George W Bush vowed the attack would not derail Iraqi elections planned for next month.

He said those who had died were carrying out a "vital mission for peace", adding that he was confident "democracy will prevail" in Iraq.

But US Defence Secretary Donald Rumsfeld, speaking at the same Pentagon news conference as Gen Myers, said the idea that insurgents would rest after elections in January was "unrealistic".

"Looking for a peaceful Iraq after the elections would be a mistake," he said.

"These guys have a lot to lose, and they are going to do everything they can to see they don't fail."

He compared the attack to the August 2003 of the UN building in Baghdad.

In other developments:

• Two French reporters return home from Iraq after being held hostage for four months

• US construction firm Contrack International pulls out of a $325m (£170m) contract to rebuild Iraq's transport infrastructure, citing security fears

• Iran bans pilgrims from travelling to Iraq after the attacks in Najaf and Karbala that claimed more than 60 lives

• Polish Prime Minister Marek Belka pays a Christmas visit to some of the 2,400 Polish troops deployed in Iraq.

'Targeted' operations

Students went to school but were told to go home. People went to the shops, saw American troops in the streets, and went home Mosul resident Mosul: Northern powder keg?

On Wednesday Mosul's governor banned the use of all five bridges into the city, and said anyone breaking the order would be shot.

Hundreds of US troops spread around neighbourhoods, backed by Bradley fighting vehicles with helicopter gunships and fighter jets overhead.

"We are conducting offensive operations to target specific objectives," said spokesman Lieutenant Colonel Paul Hastings.

City streets were deserted, with shops and even mosques closed, residents in the city of two million - and Iraq's third largest - said.

Mosul was a relatively peaceful city until last month

"Students went to school but were told to go home. People went to the shops, saw American troops in the streets, and went home," a resident told Reuters news agency.

The attack has been claimed by militant group Ansar al-Sunna, thought to have links with leading Jordanian militant Abu Musab al-Zarqawi.

Mosul has experienced a wave of violence since last month's offensive on the former rebel stronghold of Falluja.

Insurgents have overrun police stations in the city, prompting most of the police force to desert.

Previously the US military's worst single incident since it invaded Iraq was a helicopter crash in Mosul in November 2003, which killed 17 soldiers.