Unknown assailants opened fire at Fuqahaa at the entrance to a residence in the Tal al-Hawa neighborhood in southwestern Gaza City, shooting four bullets into the man’s head before they fled the area, witnesses said.
The assassination was carried out with a gun equipped with a silencer, according to member of Hamas’s politburo Izzat al-Rishq.
Fuqahaa, originally from the northern occupied West Bank district of Tubas, was released from serving a life sentence in Israeli custody in the 2011 Gilad Shalit prisoner exchange deal, and then exiled to the besieged Gaza Strip.
According to Israeli media, Fuqahaa was a senior member of the Izz al-Din al-Qassam Brigades, and had been sentenced to life in prison after being accused of planning a suicide bombing in northern Israel in 2002 that left nine people dead and tens of others wounded.
Israeli news site Ynet reported that after his release, Fuqahaa helped found Hamas' West Bank headquarters and manage it from Gaza, claiming he has also since "helped organize and conduct terror attacks against Israelis."
In a statement, the brigades said that it was “clear and obvious that this crime was arranged by the Zionist enemy,” referring to the state of Israel.
They went on to warn that “this enemy will be the ones who suffer the consequences and take responsibility for this crime,” and that Israel would “regret the day” they began carrying out stealth assassinations against “resistance fighters in Gaza.”
The Hamas movement called the assassination “a cowardly attack by the occupation,” promising that Israel would “pay for its crimes.”
Fuqahaa's father, who still lives in Tubas, told Asra Radio
that he also accused Israel of the assassination. "Israeli intelligence officers came to our house many times and gave us messages that Mazen would be liquidated if he continued with his actions," the report quoted him as saying.
The Abu Ali Mustafa Brigades, the military wing of the leftist Popular Front for the Liberation of Palestine also denounced the assassination, saying the killing “must be met with a harsh response by all resistance factions.”
The Islamic Jihad movement said Fuqahaa’s assassination marked the start of “a new offensive” by Israel against Palestinian resistance, and that the resistance had the right to respond and defend themselves.
Spokesperson for Gaza’s Ministry of Interior Iyad al-Buzm said security services had opened an investigation into the details of the incident.
On Saturday, thousands of Palestinians took part in a funeral march for Fuqahaa, including members and leaders from various political factions and armed groups.
The funeral set off from Gaza City's al-Shifa Hospital, where Fuqahaa's body had been taken after he was killed.
Funeral prayers were held at al-Omari mosque in Gaza City, before the march continued toward Sheikh Radwan cemetery in the north side of the city for burial.
He was reportedly shot at close range while he was in his car with six bullets -- three to his head, according to Israeli daily Haaretz.
The Mossad, Israel’s foreign intelligence agency, reportedly targeted al-Zouari due to his work manufacturing drones for Hamas.