The leader of a radical Islamist group involved in a shootout with Hamas in Gaza is one of at least 22 people killed in the raid, according to reports.

Abdul-Latif Moussa died in an explosion, officials said, but it was not clear whether he blew himself up.

On Friday Hamas, which controls Gaza, launched a bloody crackdown on the group, Jund Ansar Allah, after it declared an "Islamic emirate".

Scores were injured in the attack on a mosque in Rafah, near the Egypt border.

Hamas also stormed Abdul-Latif Moussa's house.

The fighting lasted seven hours and ended at about midnight on Friday.

Followers of the group said Abdul Latif-Moussa blew himself up in a crowd of Hamas police, but Hamas has denied this.

Six Hamas fighters, including a senior commander, and one civilian died. The rest of those killed were from Jund Ansar Allah.

About 120 people were injured, with some in a critical condition.

A Hamas spokesman said: "We hold Abdul-Latif Moussa and his followers fully responsible for what happened because of his hasty declaration during Friday prayers of a so-called 'Islamic Emirate'."

The Jund Ansar Allah (Soldiers of the Companions of God) is thought to be linked to al-Qaeda.

"Anyone who belongs to this group has to immediately hand himself and his weapons over to the Palestinian police and security forces," the spokesman said.

Hamas fighters on Friday fired rocket-propelled grenades at Ibn-Taymiyah mosque, where at least 100 Jund Ansar Allah supporters were holed up.

The entire neighbourhood was sealed off as the shooting continued after dark - in what was one of the most violent incidents in the Hamas-controlled Gaza Strip since an Israeli offensive in December and January.

Abdul-Latif Moussa and his armed supporters had sworn to fight to the death rather than hand over authority of the mosque to Hamas.

During his own Friday sermon, the leader of Hamas in Gaza, Ismail Haniya, dismissed Moussa's comments.

"These declarations [of an Islamic emirate] are aimed towards incitement against the Gaza Strip and an attempt at recruiting an international alliance against the Gaza Strip.

"And we warn those who are behind these Israeli zionist declarations: the Gaza Strip only contains its people."

Jund Ansar Allah gained some prominence two months ago when it staged a failed attack on horseback on a border crossing between Gaza and Israel.

The group is very critical of Hamas, which seized Gaza in 2007, accusing the Islamist group of not being Islamist enough.