Baghdad: The United Nations mission in Iraq urged US forces yesterday to pursue a 'vigorous' probe into an air strike that killed 15 women and children and said its findings must be made public so that lessons can be learned.

It said the safety of civilians should be a top priority during military operations. In a human rights report published on Thursday, the same day as the attack, the mission highlighted the number of Iraqi civilians killed in recent US air strikes.

"Civilians are getting caught far too often between warring combatants," said UN mission spokesman Saed Erekat. "We understand the security concerns, but we also hope that every possible safety measure is taken not to harm any civilians.

The US military said it was conducting a "thorough investigation" into the strike by its attack helicopters on a suspected meeting of senior Al Qaida leaders north of Baghdad on Thursday that killed nine children, six women and 19 insurgents.

"In every instance we take as many precautions as possible to ensure innocent lives are not at risk," military spokesman Rear Admiral Greg Smith said.

"We are committed to working with affected families and taking care of their needs."

The US military says insurgents often deliberately hide among civilians and previous air strikes on suspected militant hideouts have resulted in civilian deaths.

In its human rights report, covering the April to June period, the United Nations Mission in Iraq said it had recorded a number of incidents in which a total of 88 civilians were reported to have been killed in US.air strikes.

Thursday's incident, on the eve of the Eid Al Fitr holiday, is likely to reignite tensions between Washington and Baghdad, which has repeatedly criticised US forces over the number of Iraqi civilians killed in military operations. "We certainly hope that they do pursue this vigorously and that these findings will be made public and lessons learned," Erekat said.

Under fire

The 15 were killed during an operation targeting senior leaders of Al Qaida in the Lake Thar Thar area 80 km northwest of the Iraqi capital early on Thursday night.

Smith said imagery from aerial drones and the helicopters was being studied to get a better understanding of how events unfolded. Under the military's rules of engagement, soldiers were permitted to take measures to protect themselves if they came under fire.

The US military said in a statement that intelligence reports and surveillance had indicated senior Al Qaida figures were meeting in the Thar Thar area. An initial air strike on the site killed four insurgents.

A bomb hidden in a cart of toys killed two children and wounded 17 others in a playground in northern Iraq yesterday, the first day of a national holiday to celebrate the end of Ramadan.

The attack came the day after US forces killed nine children and six women in an air strike northwest of Baghdad targeting suspected Al Qaida leaders.

Police Colonel Abbas Mohammad said a would-be suicide bomber pushed the cart into a play area in the predominantly Shiite town of Tuz Khurmato. He said the bomber was wounded.

The town's mayor, Mohammad Rasheed, said two boys aged between 10 and 12 had died and another 17 people under the age of 18 had been wounded in the deadly attack. A youth with a smashed, bloodied face and mangled hand lay on a hospital bed in the nearby city of Kirkuk after the attack.

A man prayed by an injured boy while doctors wreathed the chest, arms and shoulders of another with bandages.

The United Nations also called for probes to determine whether private security contractors in Iraq have committed war crimes by killing civilians and for governments to ensure that the rule of law is applied.