Skirmishes first broke out last week between the Palestinian Islamist group and the Doghmush clan after a ceasefire between Israel and Hamas came into effect.

On Sunday evening, gunfights took place in the Sabra neighbourhood of Gaza City, according to witnesses who spoke with AFP on condition of anonymity, citing fears for their safety.

"About 200 members of the (Hamas) security forces were present and fought until they completely subdued" the clan members, a local resident said.

"There were dead and wounded among the (Doghmush) family members, but also martyrs and injured among the security forces," he added.

Another neighbour gave a similar account, saying calm returned to the neighbourhood only around 9:30 pm (1830 GMT).

A source within Gaza's Hamas-run Interior Ministry acknowledged that there had been fatalities on both sides.

Accusing the Doghmush clan of being affiliated with Israeli forces and of having carried out several murders, the ministry source said around sixty members of the family had been arrested.

The family denied any collaboration with Israel, but admitted in a statement that some of its members had committed "transgressions", without further detail. It further accused Hamas security services of targeting all its members indiscriminately.

"In recent days, it was enough to belong to the Doghmush family to be shot in the legs, killed, arrested, or have your house burned down," declared Abu al-Hassan Doghmush, a leading clan figure, on Facebook.

Following its seizure of power in the Gaza Strip in 2007, Hamas has had repeated violent confrontations with Gaza's clans, including the Doghmush.

On Sunday, Gaza's interior ministry announced the opening of a "general amnesty period" for "members of criminal gangs" who had not committed murders during the war.

Since the ceasefire came into effect on Friday, AFP reporters have observed Hamas security forces deploying in several urban areas, markets and along roads across the Gaza Strip.