Two Taliban leaders were killed and two others were captured as part of the NATO coalition's stepped up campaign against the insurgency's mid-level command structure and its supply lines, the coalition said on Monday.

Also on Monday, about 300 to 400 people protested the capture of nearly a dozen people in an overnight raid in Behsud district of Nangarhar province in the east, said Hazrat Mohammad, a spokesman for the provincial police chief.

The demonstrators claimed that those apprehended in the coalition raid were not insurgents. The coalition said it was investigating the claims.

A joint Afghan and NATO force killed Fared Gul, who was involved in planting roadside bombs and organizing attacks on coalition convoys and aircraft, during an overnight operation in Zurmat district of Paktia province, the coalition said.

NATO also reported that Hafiz Janan, a key Taliban leader involved in training foreign fighters, was killed Saturday in the Bakwa district of Farah province in the west. Another Taliban leader was captured in Baraki Barak district of Logar province, south of Kabul.

Afghan and coalition forces also captured a key Taliban leader of a bombing ring and several suspected insurgents in the Lashkar Gah district of Helmand province on Sunday.

The insurgent leader is based in the Dand district of neighboring Kandahar province and is responsible for violent attacks on Afghan civilians and coalition forces. He also is suspected of planning a heavy machine gun ambush on coalition forces, intimidating civilians and training insurgents to execute bomb attacks.