"The occupation's bombing last night and today on the Gaza Strip led to the killing of four of the enemy's prisoners," the Ezzedine al-Qassam Brigades, the armed wing of Hamas, said on its website.

AFP could not verify the claim, which comes after dozens of people were taken hostage by the militants in attacks across southern Israel on Saturday.

The Israeli military did not immediately comment on the deaths of "prisoners" when contacted by AFP.

More than 700 people have been killed in Israel, officials said, the majority slain by militants who crossed the border from Gaza by land, air and sea.

Israel has retaliated with repeated strikes on Gaza, where at least 560 have been killed according to health officials in the Palestinian territory.