Dozens of land-mine-removal workers were kidnapped and held for seven hours in Afghanistan on Tuesday, the largest mass abduction in the country in years and the latest sign of worsening militant activity.

The 63 men were freed after village elders intervened and security forces flooded the district where they were held, said Farid Homayoun, manager of the Afghanistan program of the British land-mine removal organization Halo Trust, which employs the workers.

“They were released unharmed,” Homayoun said. “The Taliban have apparently said they were not behind it, and the identity of the kidnappers is not clear to us.”

The workers were seized from their office in the restive Pashtun Zarghun district of western Herat province, Gov. Sayed Fazlullah Wahidi said. Ten armed men came to the site on motorbikes and forced the employees to drive to a nearby village, Homayoun said.

“The gunmen opened fire on our vehicles, causing damage to them, and then took the employees to a mountain,” Homayoun said. “Eight of them managed to flee.”

Abduction has become a lucrative business for insurgents and criminal groups in Afghanistan, where U.S., NATO and Afghan forces are trying to suppress a resurgent Taliban.

Militants in the past have freed some captives after apparent payment of ransom. But they have also killed captives when their demands were not met.

Homayoun and an officer with the Mine Action Coordination Center of Afghanistan, the main umbrella body for mine-clearance groups in the country, said the motive for Tuesday’s abductions was not clear.

The abductions come amid a rise in suicide attacks and other insurgent activity in various parts of the country.

On Friday evening, militants stormed a well-known Lebanese restaurant in the heart of Kabul and killed 21 people, including the proprietor and 13 foreigners — three of whom were American.