U.S. and allied forces denied Monday a claim from Hamid Karzai's Afghanistan government that 45 civilians were killed by a rocket attack last week.
Karzai said earlier Monday that a rocket fired by NATO troops killed "52 innocent civilians" in southern Afghanistan.
An investigation by the National Directorate of Security found that a house in Helmand province's Sangin district was hit on Friday "by a rocket launched by NATO/ISAF troops, leaving 52 civilians dead, including women and children," a statement from Karzai's office said.
"The president condoled via phone with the mourning families and called on NATO troops to put into practice every possible measure to avoid harming civilians during military operations," it said.
NATO, however, said none of its initial reports confirmed any civilian deaths in the area or NATO rockets going astray.
"I don't have any operation reporting to corroborate the reports of civilian casualties," said Col. Wayne Shanks, a spokesman for NATO and U.S. forces.
He said NATO forces battled insurgents Friday in an area about seven or eight kilometers (four or five miles) away. Helicopters were called in that fired rockets in support of ground forces but there was no evidence in initial reports that this firefight was connected to the claims of rocket fire in Regi, Shanks said.
An assessment team traveled to Helmand on Monday to further investigate the claims, he said.
The Associated Press and NewsCore contributed to this report