Two others were wounded when police opened fire to control the angry mob that obstructed the highway in eastern Nangarhar province to demand the return of five men abducted as part of the dispute, a deputy governor said.
"One protestor was killed and two others were wounded mistakenly by police," Mohammad Alam Ishaq told AFP. A witness said two were killed and two wounded.
The dispute erupted seven months ago when the Gardiwal and Paikhawal tribes clashed over land. Gardiwal men later abducted five men from the rival group, Ishaq said.
The Paikhawal protest, which blocked the road to the border with Pakistan, turned violent when someone in the crowd started throwing stones at police, provoking a reaction. The protestors wanted government help in securing the release of the five.
Tribal disputes are not uncommon in Afghanistan, especially in the deeply traditional south and east, and can turn into fierce battles with many men carrying arms after nearly 30 years of war.

Copyright AFP (Agence France-Presse), 2006