Gaza City - Hamas police in the Gaza Strip battled it out with one of the salient's most powerful clans Tuesday, leaving at least 11 people, a baby infant among them, dead, in the worst internecine violence in the salient in more than a month.

Dozens of people were also injured in the fighting, which saw both sides use rocket-propelled grenades and semi-automatic weapons.

The clashes erupted when Hamas police forces raided a neighbourhood in southern Gaza City before dawn, seeking to arrest members of a powerful local Dughmush clan.

A statement by the Hamas-controlled Interior Ministry said the police killed three "wanted criminals" who refused to surrender during an attempt to arrest them.

The radical Islamist movement ruling Gaza ordered the raid after one clan member killed a Hamas policeman and wounded another when police tried to arrest him near a Gaza City market on Monday.

Jameel Dugmush fled to the family's stronghold in the al-Sabra neighbourhood, prompting Hamas to send its forces into the area after him.

Ihab al-Ghussein, a spokesman for the Hamas Interior Ministry, said "the security campaign in al-Sabra neighbourhood is over."

"All the wanted criminals were killed in the operation," he added in a statement sent to the media. "This was not a campaign against the Dugmush family. It only targeted some members of the family involved in security chaos."

"We will not allow more security strongholds in Gaza Strip to cause anarchy and threaten the safety of the residents," Islam Shahwan, a Hamas police spokesman, said.

Tuesday's clashes were the worst since early August, when a Hamas raid on the pro-Fatah Helles family in Gaza City's Sheja'eya neighbourhood left some 13 Palestinians dead and dozens more wounded.

Most of the large clans in Gaza Strip are loyal to Fatah, but after the Hamas Gaza takeover made their peace with the Islamist movement.

The Dughmush clan did not however, but Hamas did not take action against the family, in part because the clan harboured in its ranks the Army of Islam, a radical group which joined Hamas in snatching an Israeli soldier during a June 2006 cross-border raid.

In addition, many Dughmush family members are active in the Popular Resistance Committees (PRC), a pro-Hamas armed group.

But relations between Hamas and the clan soured when the Army of Islam kidnapped BBC correspondent Alan Johnston and held him for several months.

Hamas has accused the Army of Islam of trying to stir disorder in the strip on the order Hamas' bitter rival, the Fatah movement of Palestinian president Mahmoud Abbas.

Hamas says Abbas' movement, which is consolidating its power in the West Bank, is behind "attempts to shake security in Gaza."

The two Palestinian movements have severed all ties since Hamas violently seized sole control in the Gaza Strip in June 2007 by overpowering the headquarters of security forces loyal to Abbas. (dpa)