The armed wing of Hamas, the Izzedine al-Qassam Brigades, announced on Thursday that three of their top commanders had been killed in an Israeli airstrike on southern Gaza.

Hamas identified the deceased as Mohammed Abu Shamaleh, Raed al-Attar and Mohammed Barhoum, among the most senior Hamas leaders to die in the current conflict to date. All three have been heavily involved in high-profile attacks in Israel.

Witnesses said the airstrike had leveled a four-story family home in the city of Rafah on the Egyptian border, which killed four others aside from the military chiefs.

According to local police and medical staff, scores remain trapped in the rubble under the destroyed house.

The Israeli security agency Shin Bet confirmed the deaths of Shamaleh and al-Attar in an email, but did not mention Barhoum, according to the Associated Press news agency.

A spokeswoman for the Israeli army stated that this offensive was one of 20 different assaults carried out during the night and early morning. Israel says these strikes are a response to renewed fire from Hamas following a six-day cease fire.

Israel has also targeted the head of Hamas' armed wing, Mohammed Deif. On Tuesday, the an airstrike targeting Deif, who heads Hamas' Izzedine al-Qassam, succeeded only in killing his wife and seven-month old son. This is one of a number of assassination attempts Deif has survived, one of which has allegedly left him paralyzed.

Egyptian-brokered negotiations broke down earlier this week. While leaders in Cairo have called on both Hamas and Israeli leaders to resume dialogue, Israeli Prime Minister Benjamin Netanyahu has vowed to continue the offensive. On Wednesday he told reporters: "we are determined to continue the campaign with all means and as is needed."

2,065 Palestinians, and 67 Israelis have died in the last six weeks of fighting. According to the UN three-quarters of the Palestinian victims were civilians.

es/kms (AP, AFP, dpa, Reuters)