MAZAR-I-SHARIF, Afghanistan -- An Afghan commander and four fighters were killed in an ambush this week in the north of the country, factions operating in the region said on Wednesday.

Ghulam Nabi, a commander from the Shiite Hezb-i-Wahdat Party, died along with four of his troops near the town of Dara-i-Suf in the Province of Samangan about 100 km (63 miles) south of the key northern city of Mazar-i-Sharif.

A Wahdat spokesman in Mazar said he did not know who was behind the ambush, AFP said.

Wahdat is one of three main factions in northern Afghanistan. Despite officially supporting the central government in Kabul their fighters frequently clash in battles for control of territory and lucrative customs revenues.

A general from another faction, the Jamiat-e-Islami Party, said the ambush took place two days ago and a team of UN representatives had gone to the area to investigate.

The general also said one Jamiat soldier was killed and one commander wounded on Wednesday in a clash with members of the third regional faction, Junbish, which is led by former communist commander General Abdul Rashid Dostum.

He said Junbish forces had reinforced areas near the town of Maimana some 200 km (125 miles) southwest of Mazar where the soldier was killed.

But Dostum's spokesman Faizullah Zaki denied there had been any fighting between the factions or reinforcements in the area.

The United Nations has made several attempts to disarm commanders and fighters loyal to rival factions in northern Afghanistan, but mutual distrust and territorial rivalries have undermined its efforts.

Dostum and Jamiat leader Ustad Atta Mohammad fought against each other during the 1990s, but united to counter the Taleban.

They proved valuable allies to the United States in its campaign to topple the hardline regime.