The U.S.-led military coalition in Afghanistan is limiting airstrikes against houses to self-defence for troops, following a strike last week that killed women and children alongside insurgents, a spokesman for the alliance said Monday.

Such airstrikes are now being designated a weapon of last resort to rescue soldiers, cutting back their use.

Though airstrikes on homes are a small part of the international operations in Afghanistan, they have brewed resentment among Afghans, even when there are no casualties, because of the sense that homes and privacy have been violated.

Civilian deaths from such operations have threatened to derail the Afghan-U.S. alliance.

A pact signed by the Afghan government and the U.S. military in April putting Afghans in charge of joint raids in villages was supposed to ease these tensions, but the aftermath of Wednesday's airstrike against a home in eastern Afghanistan has shown that the Americans are still making the decisions on the ground.

Afghan officials have said that 18 civilians were killed in the strike. President Hamid Karzai rebuked U.S. forces for failing to consult their Afghan counterparts before calling for an airstrike in the house where insurgents had taken cover. NATO discovered that civilians had died the next morning when villagers piled the bodies into vans to display to Afghan officials.

Karzai demanded in a meeting Saturday night with NATO and U.S. forces commander Gen. John Allen that the international troops ban all airstrikes on homes.

Strikes limited to saving lives of troops

A spokesman for the alliance, Lt. Col. Jimmie Cummings, said Monday that airstrikes were being severely curtailed.

"We will continue to conduction combat operations against insurgents who use civilian dwellings, but we will not use air-delivered munitions against civilian dwellings unless it is a question of self-defence for our troops on the ground," Cummings said.

Commanders previously could order airstrikes against insurgents on houses, as long as they were confident that there were no civilians present. Cummings says that the new restrictions mean commanders will not be able to call in a strike unless it is necessary to save the lives of their troops. This applies even if it is clear there are no civilians in the house.

"This restriction in no way limits our ability to take the fight to the enemy," Cummings said. He said that of about 3,000 NATO airstrikes in the past six months, only 10 of them were against civilian homes. Of those 10, seven resulted in civilian casualties, he said.

In addition, he said, NATO forces are in negotiations with Afghan officials about how to involve the Afghan military in decisions on airstrikes. Afghan forces have already had to sign off on joint operations in villages, but there has not been a procedure for involving them in the often split-second decision of when to call in air power.

Last year was the deadliest on record for civilians in the Afghan war, with 3,021 killed as insurgents stepped up suicide attacks and roadside bombs, according to the United Nations. The number of Afghan civilians killed dropped 36 per cent in the first four months of this year compared with last year, though UN officials have said that a likely cause of the drop in violence was the particularly harsh winter.

Anti-government forces, including the Taliban and other militants, were responsible for 79 per cent of civilian casualties in the first four months of this year, according to the U.N. tally, while Afghan and international forces were responsible for nine per cent.

UN fires 3 Afghan officials over fraud allegations

Violence has started to increase with the warm summer weather, including regular reports of civilian casualties. Nine civilians were killed Monday in two separate incidents, including one in which an ambulance rushing a pregnant woman to a hospital struck a roadside bomb. The woman and four of her family members were killed in the blast in Sar-e-Pul province, the Interior Ministry said.

Another two women and two children were killed Monday in the east when a mortar fired by insurgents hit their home in Ghazni province's Gilan district, said Ghazni provincial spokesman Fazel Ahmad Sabawon. The militants appeared to be aiming for a government building nearby, he said.

In another development, the United Nations reported that it fired three Afghan officials as part of an investigation into allegations of fraud in the management of a $1.4-billion US fund for the training and support of the Afghan police force. The program, which pays police salaries, is an important part of the effort to maintain security in Afghanistan as international forces draw down over the next two years.

"This ongoing investigation indicates zero tolerance toward fraud," said Brian Hansford, a spokesman for the UN Development Program, which oversees the Law and Order Trust Fund for Afghanistan. He declined to give specific information on those fired or the exact accusations. It was not immediately clear how much money was involved.