The pre-dawn air strikes targeted several homes and residential buildings across the besieged Gaza Strip, resulting in the murder of Jihad Ghannam, 62, Khaled Al-Buheiti, 44, and Tareq Izz al-Din, as well as members of their households, including women and children, reported the palestinian news agency WAFA.

An AFP journalist in Gaza saw the top of a building on fire immediately after the strikes as well as ambulances evacuating victims.

​In Rafah, in the south of the Gaza Strip, an AFP photographer saw the body of a man identified as Ghannam.

Explosions from air strikes, which began a little after 2 am (2300 GMT), could be heard for nearly two hours, according to AFP journalists.

The Israeli occupation army said the strikes, involved 40 aircraft and had targeted three leaders of the Islamic Jihad, a Palestinian militant group based in Gaza, and claims to have hit "weapon manufacturing sites" belonging to the group.

"We mourn the leaders and their wives and a number of their children who were killed in a cowardly Zionist crime," Islamic Jihad said in a statement, vowing "the blood of martyrs will increase (the) resolve" of the movement.

The operation came less than a week after Islamic Jihad announced a truce around Gaza -- brokered with help from Egypt -- following a fresh flare-up in violence.

Israel and Gaza militants traded cross-border fire following the death in Israeli detention of Khader Adnan, who had been on hunger strike for 87 days following his arrest with any charges.

On Tuesday, the militant group said Israel had "scorned all the initiatives of mediators" and vowed it would "avenge the leaders" killed in the latest air strikes.

The Palestinian Ministry of Foreign Affairs and Expatriates strongly condemned the attack. In a statement, the ministry called the attack a "heinous crime" and stated that it is part of the occupation's ongoing war against the Palestinian people and their legitimate national rights, WAFA reported.

The statement also accused the Israeli government of trying to export its internal crises to the Palestinian arena and resolve them at the expense of the Palestinian people.

The ministry held the Israeli government responsible for the aggression and its consequences, warning that it could lead to a dangerous escalation that threatens the region's stability and called on the international community to take urgent action to stop the Israeli aggression against the Palestinians and stressed the need for a negotiated political settlement to the conflict as the only way to achieve security and stability.

Hamas chief Ismail Haniyeh said "assassinating the leadership in a treacherous operation will not bring security to the occupier, but instead greater resistance".

The militant group's spokesman, Hazem Qassem, warned that Israel "bears responsibility for the repercussions of this escalation".

Tuesday's casualties bring to 121 the number of Palestinians killed in the Israeli-Palestinian conflict so far this year.

In the occupied West Bank, 12 Palestinians were detained early Tuesday in a series of home-raids carried out by Israeli occupation forces, WAFA reported, citing local and Palestinian security sources.

Of the 12 were seven siblings rounded up in the town of Yatta, while two others were detained in the city of Hebron and three others in Ramallah, one detained at a checkpoint outside Ramallah.

In al-Mughayyer, seven others were detained and held for several hours before they were released, sources added to WAFA.