(Adds Pentagon comment, paragraphs 9-13)

JALALABAD, Afghanistan, Nov 28 (Reuters) - NATO air strikes killed 12 civilian road workers in eastern Afghanistan, a provincial governor said on Wednesday, an incident bound to fuel Afghan resentment against the presence of international forces.

NATO has tightened procedures for launching air strikes after Afghan President Hamid Karzai warned of rising anger over mounting civilian casualties, but military commanders say some civilian deaths are almost inevitable in any conflict.

Foreign forces have a limited time to weaken Taliban rebels and allow development to undercut the insurgency before Afghans turn against the international presence and Western public opinion demands troops be brought home, security analysts say.

"So far we know that 12 people have been killed by U.S. bombardment," Tameem Nooristani, governor of the eastern province of Nooristan, told Reuters. "They were only poor and innocent road construction workers."

U.S. troops had been tipped off that a feared local Taliban commander was in the area, he said, but hit the wrong target.

The NATO-led International Security Assistance Force (ISAF) said air strikes had been launched against entrenched Taliban positions in the area on Tuesday and an investigation was underway to determine if civilians had been killed.

"ISAF was engaged in Noor Galam and Dowa, in those places we used air strikes against Taliban," ISAF spokesman Brigadier General Carlos Branco told a news conference.

"The situation is not clear at all at this stage, we are carrying on an investigation ... but for the time being there is no definitive assessment," he said.

The Pentagon said later on Wednesday that a Taliban commander may have been killed in the air strike and that the nearest known construction site was more than a kilometer away from the site of the incident.

"There were no structures, vehicles or any other construction equipment within the vicinity of the impact area," Pentagon press secretary Geoff Morrell told reporters.

"We believe that Abdullah Jan, the western Nooristan Taliban commander, may have been killed in the air strike. We deem it, at this point, a legitimate air strike."

A provincial police chief reported back in September that a Taliban leader named Abdullah Jan had been killed in an air strike.

While almost all ISAF troops on the ground in eastern Afghanistan are American, aircraft from a number of NATO countries may respond to a request for air support.

The head of the Afghan road construction company said 25 of its workers were killed in the incident. Nineteen bodies were brought to a hospital in the eastern city of Jalalabad, a doctor there said.

It was not possible to independently verify the incident due to the danger and remoteness of the area.

Afghanistan has seen a steady rise in violence since the Taliban relaunched their insurgency to overthrow the pro-Western Afghan government and eject more than 50,00 foreign troops two years ago. (Reporting by Noor Mohammad Sherzad; Additional reporting by Andrew Gray and Kristin Roberts in Washington; Writing by Jon Hemming; Editing by Jerry Norton and Ibon Villelabeitia)

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