Clashes renewed between he PA security forces and Hamas operatives late Monday night when a pro-Hamas research center was set on fire by unknown masked men.

Palestinian sources said nine were injured in the clashes including three of the Aqsa Martyr brigades of Fatah who did not take part of the previous clashes, besides, several PA security and Hamas vehicles were set on fire during the clashes, that lasted through the night.

The clashes, the source said are mainly focused in Beit Lahia and Jabalia refugee camps in the northern part of the Strip.

The center has recently published a study saying that had the elections been held on its original date, July 17, at least 51 per cent would vote for Hamas and only 21 per cent would vote for Fatah.

An Egyptian mediation managed to end the clashes between Hamas and the Palestinian Authority.  Clashes originally erupted when PA security opened fire at Hamas activists preparing to fire Qassam shells at Israeli targets last week.

Two Palestinians were killed and over 20 were injured in last week clashes.

During meetings with the Egyptian delegation to the Gaza Strip, Hamas agreed to cease calling for the dismissal of Interior Minister Nasser Yousef, the sources said.

The Palestinian Authority insists that there is only one authority and one legal weapon in the Palestinian controlled areas.