Clashes broke out in Gaza City on Sunday, wounding at least six people, as Hamas-run security forces pressed on with a territory-wide crackdown on rival Palestinian factions after a deadly bombing. The fighting erupted when Hamas-run police moved to arrest members of the Army of Islam, a small shadowy group believed to have links to Al-Qaeda.

"Hamas forces came to arrest us early this morning, just after midnight," one member of the group who asked not to be identified told reporters.

"There was fighting for several hours, with rocket-propelled grenades, explosions and gunfire, but they did not arrest anyone," he added.

At least six people were wounded in the clashes, said a medic at Gaza's main Al-Shifa Hospital who also asked not to be identified.

The clashes came as Hamas cracked down on rival movements it suspected of planting a bomb on Friday night that killed five senior members and a 5-year-old girl in the deadliest Palestinian attack on the group since it seized power in the Gaza Strip in June 2007.

Hamas on Saturday blamed the attack at a Gaza City beach club popular with its members on Palestinian President Mahmoud Abbas' Fatah party, which it accused of trying to undermine its rule.

Fatah has denied any involvement in the blast and said the attack was part of an internal Hamas conflict.

Since the explosion Hamas-run forces have arrested more than 300 people, according to senior Fatah officials, most of them members of the movement which was largely expelled from Gaza when Hamas seized control.

Hamas forces raided the houses of two Fatah leaders, Zakariya al-Agha and Ibrahim al-Naja, and confiscated their cars, a senior Fatah official said on condition of anonymity.

Security forces have also raided more than 120 offices, sporting clubs and charities, most of them linked to Fatah, confiscating computers and documents, according to the independent Al-Mizan Center for Human Rights.

Abbas' security forces in the Occupied West Bank meanwhile arrested 34 Hamas members in separate raids across the Israeli-occupied territory, according to a senior Palestinian security official.

He denied there was any link between the arrests and events in the Gaza Strip.

The two main Palestinian factions have been bitterly divided since Hamas seized power in Gaza, but the factional clashes that rocked the impoverished coastal territory of 1.5 million people before the takeover have mostly ceased.

Hamas denied that the latest string of arrests was political.

"There were only a limited number of people arrested, and most of them were later released," Hamas spokesman Sami Abu Zuhri told AFP, without providing a precise count of how many had been detained.

"We condemn this focus on the arrests, which are connected to the murder of five fighters and a child, while everyone ignores those who were arrested in the [Occupied] West Bank for political reasons," he added.