About 40 masked fighters from the al-Aqsa Martyrs' Brigades, an offshoot of the Fatah party, also on Wednesday stormed the headquarters of the Palestinian legislative council and the electoral central committee in Rafah.
The armed group had earlier stormed the headquarters of the Interior Ministry in the city in protest against the arrest of their colleague by Palestinian security forces on Tuesday over suspected involvement in the abduction of three Britons last week.
On Tuesday, Palestinian intelligence arrested Alaa al-Hams on suspicion he and his followers kidnapped human rights activist Kate Burton and her parents for two days last week.
The Burtons were among 19 foreigners abducted by Fatah gunmen in Gaza in recent months. All have been freed unharmed.
On Wednesday morning, some of the armed men took over the central election office in Rafah, the local branch of the Palestinian parliament, a local court and another government building.
The gunmen blocked access to
the Gaza-Egypt border
A truckload of armed men then drove to the nearby Rafah border crossing, Gaza's main gate to the world.
Firing in the air, they closed the entrance gate to the crossing compound and told waiting travellers to leave the area.
One of the fighters, who gave his name as Ahmed, said the group was demanding al-Hams' release.
In another development, a 38-year-old Palestinian was shot dead on Wednesday by the Israeli occupation army in the Hebron region of the southern West Bank, medical and military sources said.
Witnesses said Mustapha Ibrahim Awlad Mohammed was killed in Tarrama, to the southwest of Hebron, when troops entered the village at daybreak.
The military said that troops who had come to arrest Mohammed had opened fire on the victim when he refused orders to lay down a weapon he was carrying.
"He directed his weapon towards the force and refused to put it down. Soldiers then opened fire on him," an army spokeswoman said.
It was not immediately known whether Mohammed was a member of any armed faction.
The latest death raised to 4928 the number of people killed since the intifada broke out in September 2000.
More than three quarters of the victims have been Palestinian.