Iraqi security officials, speaking to AFP on condition of anonymity, said that the clashes late Saturday erupted over increased fees for a private power generator.

The vast majority of Iraqis rely on private generators to compensate for daily long power cuts to public electricity.

The violence Saturday in Baghdad's Saada area resulted in the deaths of four police officers, two of them commanders, after they had intervened to disperse a "tribal dispute", the interior ministry said, revising an earlier toll.

A security official, requesting anonymity because he was not authorised to brief the media, said the toll was updated after two policemen succumbed to their injuries.

Another nine officers were wounded, the ministry said.

It said the force was attacked by "those who started the clashes", and returned fire that killed two people.

Five of those involved in the clashes were wounded and several arrested, the ministry said.

Tribal feuds are common in Iraq, a war-scarred country awash with weapons, where the pettiest row can turn into deadly tribal clashes.

Tribes wield significant influence and often operate under their own moral and judicial codes, and they possess huge caches of arms.

Iraq has only recently begun to regain a sense of stability after decades of violence that followed the 2003 US-led invasion that ousted long-time ruler Saddam Hussein.