Nato says it is confident that reports that it killed a number of civilians in an air strike in Nuristan province on Monday are incorrect.
Brig Gen Branco - Isaf 'still verifying reports'
The provincial governor has said that 12 construction workers died.
But a spokesman for the Nato-led Isaf force says evidence so far "points to a successful strike" against a Taleban leader with no civilian deaths.
Last week, Nato head Jaap de Hoop Scheffer had said it was doing all it could to avoid civilian casualties.
"Evidence so far collected by Isaf investigators strongly points to a successful air strike earlier this week against a known Taleban leader in Nurgaram District of Nuristan province and that there were no civilian casualties," a statement issued by Isaf spokesman Brig Gen Carlos Branco, said.
"There was also no construction equipment or materials at the target site which would indicate the presence of any construction workers in the area.
"Five bodies were recovered at the target site by workers from the Amerifa road building firm," Brig Gen Branco said.
"We are trying to verify reports that on Tuesday, the Amerifa employees said the bodies were those of Taleban insurgents, but that on Wednesday, the employees claimed the bodies were those of their fellow workers."
The spokesman said: "It is our belief that once all the evidence is in, the conclusion will be a successful strike against a known Taleban leader with no civilian casualties."
Provincial officials had said the men were killed in their tents as they slept.
Nato and US military officials say they were targeting a local Taleban commander, Abdullah Jan, in Nuristan, 180km (112 miles) north-east of the capital, Kabul.
The US military has said the bombs hit a site 1km (0.6 miles) from the road workers' camp.
On Wednesday Pentagon spokesman Geoff Morrell said: "We believe that Abdullah Jan, the western Nuristan Taleban commander, may have been killed in the air strike. We deem it, at this point, a legitimate air strike."
'Enemies of the Afghans'
The governor of Nuristan and the head of the Amerifa Construction Company said Amerifa workers had been killed in the incident, which took place late Monday.
"I don't think the Americans were targeting our people," said Amerifa director Sayed Nurullah Jalili.
"I'm sure it's the enemy of the Afghans who gave the Americans the wrong information."
Governor Nuristani told AFP news agency: "We had reports that rebels were there.
"There was an air strike by coalition forces but later we found out that 12 people, all local road workers, were killed.
"The road workers were in a tent which was hit by one bomb. All died," he said.
Nato has come under increasing pressure over Afghan civilian casualties.