At least seven children were killed in a U.S.-led coalition air strike on a religious school in Afghanistan, the coalition said on Monday, amid rising anger over civilian deaths from foreign military operations.
A U.S. military spokesman said some children who survived Sunday's raid said insurgents had forced pupils to stay inside the madrasa.
"We had surveillance on the compound all day and saw no indications there were children inside the building," said Army Major Chris Belcher, a coalition spokesman, in a statement.
In Washington, White House spokesman Tony Snow said: "Obviously any time innocents are killed it is something that is a tragedy and certainly we grieve for those who are lost.
"We also understand that ... the Taliban and other terrorists try to transform innocents into human shields."
The air strike on the school occurred on the same day a suspected suicide bomber killed more than 20 people in an attack on a police bus in the heart of Kabul.
That attack indicated "the terrorists are certainly willing to go in and take innocent human lives," Snow said.
"It means that the terrorists are still active and we have to continue to fight them on all fronts."
Other violence around the country made Sunday one of the bloodiest days since the Taliban were driven from power in 2001.
The U.S.-led and Afghan forces killed several dozen insurgents in a "prolonged battle" in the southern province of Helmand that day, the U.S. military said on Monday.
The forces were attacked by an unknown number of guerrillas, prompting the troops to call in air support. Two coalition soldiers were wounded in the battle, it said, adding it had no report of civilian casualties.
Also on Sunday, in a separate incident, three coalition soldiers and their Afghan interpreter were killed after a roadside bomb hit their vehicle near Kandahar in the south.
A 44-year-old Dutch soldier was killed and three injured fighting with coalition forces in the nearby Chora region on the weekend, military officials announced in Amsterdam on Monday.
The air strike on the madrasa occurred in the southeastern province of Paktika near the Pakistan border.
The coalition said it had been part of an operation aimed at a compound containing a mosque and a madrasa thought to have been used as a safehouse by al Qaeda fighters.
"Witness statements taken early this morning clearly put the blame on the suspected terrorists, saying that if the children attempted to go outside they were beaten and pushed away from the door," the coalition said.
There was no immediate way of confirming the coalition claims.