The Israeli army said not a single shot was fired by Israel. The Palestinian Interior Minister, feeling unable to restore order, resigned. Parliament has cancelled its Tuesday session in Gaza.
An eyewitness told a local broadcaster that the gunmen, after mortar-shelling a PNA security base near a critical crossing on the border with Israel, ambushed the backup called onto the scene, killing eight officers.
The Israeli Army promptly denied Palestinian reports that the skirmish drew fire from the other side of the Karni checkpoint.
"We closed down Karni and have in no way interfered in whatever happened on the Palestinian side," an Israeli military spokesperson said.
The PNA source also said two other officers loyal to Fatah were killed elsewhere. One Hamas gunman is reported dead.
Resigning as Palestinian Interior Minister, Hani al-Kawasmeh said he lacked "real authority" and "could not restore order," as he felt "straight-jacketed."
The pro-presidential Fatah and the more belligerent Hamas, two religious Islamic groups dominating politics in the Palestinian territories, have been fighting a relentless turf war since Hamas won control of the government in a democratic election last year.
Hamas has refused to recognize Israel and has repeatedly criticized PNA President Mahmoud Abbas for his policies.
The recent outbreak of violence is the first since March, when a national unity government was formed. In the past three days, numerous attempts to broker a truce have been quickly upset by skirmishes.
