KABUL, Afghanistan - A group of Iranian and Afghan road construction workers kidnapped earlier this week in western Afghanistan has been released, police said Wednesday.

The crew of at least 12 Iranians and two Afghans was driving toward its job site in a remote part of Farah province Monday when the men were ambushed and taken hostage. The Taliban claimed responsibility for the kidnapping and threatened to kill the men off one by one unless their company stopped work on the road.

Insurgents regularly target government projects such as roads as symbols of the central government they reject and have said those who work on such projects are collaborators, not civilians.

But the police were able to secure the release of all the captives with the help of local tribal elders, who acted as mediators with the insurgents, said provincial police chief Gen. Sayed Mohammad.

Three of the men were released late Tuesday and the rest on Wednesday, Mohammad said. He said that 13 Iranians had been held, while the Iranian government reported only 12 of its citizens taken hostage. The reason for the discrepancy in numbers was not clear.

No conditions were put on the release of the captives and no ransom was paid, Mohammad said.

The Iranian company, called Jahidi Nasri Tehran, has been contracted to produce 75 miles (121 kilometers) of road in Farah and has completed about half, according to provincial Public Works Ministry officials.