MOSUL, Dec 22: US forces sealed off entire districts of the Iraqi city of Mosul on Wednesday, blocking bridges and raiding homes in a hunt for suspects after an attack that killed 18 Americans and four other people.
Mosul's governor issued an overnight order on television banning use of the five bridges over the River Tigris and said anyone breaking the order would be shot. Residents said Iraq's third city was a virtual ghost town, with no one in the streets.
FBI and other experts flown in from Baghdad were "in the middle of" determining what caused Tuesday's explosion at the Marez base in Mosul, Lieutenant-General Thomas Metz said. "If it was a bomb, I think they'll be able to figure out the size and the kinds of materials that were put into it," he told CNN.
The military declined comment on an ABC television report that investigators found evidence that a suicide bomber carried out the deadliest attack on Americans since they invaded Iraq.
"Investigators at the base have found remnants of a torso and a suicide vest that was probably a backpack," ABC said, lending weight to a claim by Iraq's Ansar al-Sunna guerrillas.
A US spokesman in Mosul, Lieutenant Colonel Paul Hastings, said: "It is still under investigation." The US military revised its description of the 22 people killed, saying 13 were American soldiers, not 14 as previously reported. It said the others were five US civilians, three Iraqi National Guards and a non-American - as yet unidentified.
US officials initially said rocket and mortar rounds were fired but Ansar al-Sunna credited one of its "martyrs" and the US commander in Mosul said there was only one explosion.
"Students went to school but were told to go home. People went to the shops, saw American troops in the streets, and went home," said Ahmad, 25, a Mosul car dealer too anxious to give his surname. "The place is shut down," said another worried resident, adding that mosques and markets were virtually empty.
The US military said a 9pm to 5 am curfew, imposed several weeks ago, remained in place. "We are conducting offensive operations to target specific objectives," Hastings said.
The attack has raised fears of a new guerrilla offensive before next month's election, six weeks after US troops stormed the rebel stronghold of Falluja in a bid to crush the insurgency. Hitherto quiet Mosul has seen near anarchy since.
"We conducted our operations last night as we planned," Metz said. "We're pushing on toward the elections." Witnesses said US forces, backed by Iraqi National Guards, sealed off neighbourhoods in western and south eastern Mosul and raided homes. "They're looking in the areas that are known hotspots," one resident in the west of the city said.
BUSH CONDOLENCES: US President George W. Bush, who said on Monday the bombers were taking a toll, sent his condolences to the families. He called Iraq "a vital mission for peace" as a new poll showed most Americans believe the war was not worth it.
The attack was a reminder of the threat guerrillas pose ahead of the Jan. 30 elections. "It was a tragic event, but it will not deter us from our mission," said Sergeant Steve Valley, a US spokesman in Baghdad.
Tuesday's attack took place when US soldiers at Forward Operating Base Marez, a huge camp built round the city's airfield, were sitting down to lunch in a vast tented hall made of canvas and metal - a type used throughout Iraq.
"A fireball enveloped the top of the tent, and pellet-sized shrapnel sprayed into the men," wrote witness Jeremy Redmon, a journalist for the US Richmond Times-Dispatch newspaper.
Mosul, an ethnically mixed city of Arabs and Kurds, has slid into chaos over recent months, especially since guerrillas routed the US-trained police in mid-November, as US troops were concentrating on storming Falluja, west of Baghdad. In the past two months alone nearly 200 people have been found dead, most of them Iraqis, in a city of two million. -Reuters