A Spanish soldier of the international brigade Plus Ultra smiles at a baby at Talavera la Real air base in Badajoz, Iraq. (AFP)

Baghdad, April 20 (Reuters): A deadly mortar barrage on a US-run prison in Baghdad killed 22 prisoners and wounded more than 90 today, a US military spokesperson said.

All the casualties at the Abu Ghraib jail just west of Baghdad were among the 4,400 people detained there on security grounds, he said.

Insurgents also attacked a US military convoy in the northern city of Mosul and one American soldier died of his wounds. Four others were injured, an army spokesperson said.

Elsewhere, tension eased in two flashpoint cities as a truce held in the Sunni bastion of Falluja and US forces prepared to pull back from a forward base near Najaf, where rebel Shia cleric Moqtada al-Sadr has taken refuge.

Witnesses said civilians who had fled battles between US Marines and Sunni insurgents trickled back to Falluja on foot, though vehicles were turned back at checkpoints.

Some shops reopened and some Iraqi police returned to duty. There was no sign of US forces in central parts of the city.

Thousands of Iraqis had left Falluja, 50 km west of Baghdad, to escape fierce fighting in which hundreds of civilians and dozens of Marines were killed this month.

The returnees were venturing back a day after the US military said it would not resume offensive operations in Falluja on condition rebels gave up their heavy weapons.

“I am confident that the guerrillas will turn in their heavy weapons as long as the Americans provide the guarantees they promised,” said Fawzi Muthin, a 47-year-old engineer who was a member of Falluja’s delegation in the talks.

US Marines launched a crackdown in Falluja on April 5 after crowds burned and mutilated the corpses of four US private security guards ambushed there on March 31.

The fighting left the city of 300,000 people littered with burnt-out cars, pock-marked walls, charred houses and a sports ground turned into an emergency cemetery.

Many of the graves are still unnamed.

“Unknown, died in al-Khadra mosque”, reads an inscription scrawled in paint on a stone leaning on a sandy mound that marks one grave. “Three children”, says another.

US forces also gave Iraqi mediators more time to resolve a stand-off with Sadr and his Mehdi Army militia in the holy city of Najaf, south of Baghdad.

General Ricardo Sanchez, commanding US forces in Iraq, told soldiers of a 2,500-strong 3rd Brigade Task Force he was pulling them back to avoid bloodshed in Najaf or damage to shrines sacred to Shias in Iraq and beyond.

“The problem of Sadr is bigger than Sadr. It is the whole Shia community and the holy shrine,” Sanchez said as troops prepared to leave a base 20 km northwest of Najaf.

“We have just about eliminated all his influence across the south,” he said, saying the cleric still had a limited presence in the towns of Diwaniya and Karbala.

Sanchez said there were “a whole bunch of initiatives” to resolve the crisis, but made clear Sadr was still a target. “Wherever we find him on the battlefield we kill him within the constraints that we have applied,” he said. Cracks have appeared in the US-led coalition as it grapples with guerrilla attacks and a wave of kidnapping only 10 weeks before a planned handover of power to Iraqis.

Spain said yesterday it had begun withdrawing its 1,400-strong contingent from Iraq. Honduras said it would pull out its 370 troops as soon as possible.

But the White House insisted the US-led coalition remained stable and said the Bush administration hoped a new UN resolution for Iraq would spur other nations to take part in providing security and reconstruction assistance.

“The coalition in Iraq is strong and their resolve is firm,” White House spokesperson Scott McClellan said.

US secretary of state Colin Powell said he had talked to the foreign minister or head of government of almost every other country in the coalition in the last 24 hours.

“And I’m getting solid support for our efforts, commitments to remain and finish the job that they came to do.”

Spanish and Honduran troops are part of a Polish-led multinational division in mainly Shia south-central Iraq.

Thailand, which has 451 troops doing humanitarian work near Karbala, said they would be withdrawn if they were attacked. But Japan reiterated that its troops would stay in Iraq, where insurgents kidnapped five of its nationals this month. All were later freed.

In Rome, the UN special envoy for Iraq, Lakhdar Brahimi, said three Italian private security guards being held hostage in Iraq could be freed soon. Kidnappers demanding the withdrawal of Italian troops from Iraq have killed a fourth Italian hostage.

The death of the US soldier in Mosul raised to 111 the number of American troops killed in action since March 31 — more than in the major combat phase of the war from March 19 to April 30, 2003, when 109 died.

A total of 509 US soldiers have been killed in combat in Iraq.

Three of four bodies found after an attack on a supply convoy in Iraq on April 9 have been identified as workers for Halliburton, the Texas-based company said today.

“We grieve today for the tragic and sudden loss of our co-workers. Halliburton extends its sincere condolences to the families of these employees,” spokeswoman Wendy Hall said.

The state department said a week ago four bodies had been found after the attack on the convoy west of Baghdad on April 9. The identity of the fourth person has not been announced.