They crossed the border into Lebanon to join Fatah forces in that country, where they set up their new headquarters.
This name has since been applied more generally to Fatah armed forces, and does not correspond to a single unit today.
It started after Fatah forces deployed on the streets of Gaza, without coordinating with Hamas.
Israel and Egypt then imposed an economic blockade on Gaza, on the grounds that Fatah forces were no longer providing security there.
The attack on Fatah forces, who were guarding the Karni crossing into Israel, was the most audacious show of force by Hamas so far.
Fatah forces did not collapse, but they did not defeat Hamas and were perceived as weaker.
He moved to Jordan in 1968 where he trained Fatah forces in Ajlun.
Fatah forces were ordered Tuesday evening to defend their positions and counter "a coup against the president and against the Palestinian Authority and national unity government."
Hamas gunmen also exchanged fire with Fatah forces at the southern security headquarters in the town of Khan Yunis.
The Fatah forces fired rocket-propelled grenades into the building of the Anour Tower and set it on fire.