Hamas gunmen executed 11 Palestinians suspected of collaborating with Israel at an abandoned police station in Gaza earlier in the day, Hamas security officials said.
Shortly afterward Hamas killed seven more Palestinians in a public execution in central Gaza square, witnesses said. Hamas warned that the same punishment will be imposed soon on others.
The executions came a day after Israel killed three top Hamas commanders in an airstrike in southern Gaza.
Hours after the targeted strike on the Hamas commanders, Ismail Haniyeh, the former head of the Hamas regime in Gaza, said, “After a senior operative is killed, we immediately continue on our path without hesitating or stepping back.”
Hamas, the militant group that holds power in Gaza, has warned that Israel will “pay the price” for killing three high-ranking leaders of its military wing, the Qassam Brigades.
Seven civilians also were killed in the bombing of the house in southern Gaza where the leaders were located. The Israeli Defence Forces said the military leaders were responsible for “major terror attacks against Israelis”.
Meanwhile, two Palestinians were killed in an Israeli airstrike on Nusseirat refugee camp early Friday morning, emergency services said. Two more were killed in an air raid near neighbouring Deir al-Balah.
Ashraf el-Qedra, spokesman for the ministry of health in Gaza, said 72 Palestinians have been killed since the two sides resumed hostilities on Tuesday after the collapse of a ceasefire and talks aimed at finding a lasting end to the fighting.
Palestinian militants fired more rockets into Israel, and the Israeli Defence Forces kept up airstrikes on Gaza. El-Qedra said 2,087 Palestinians have been killed since the conflict began in early July. The United Nations estimates that around 70 per cent of the dead were civilians.
The fighting has killed 67 people on the Israeli side, almost all of them soldiers. The truce fell apart after Israel reported that militants had started firing rockets again.
Since the fighting flared up again this week, 360 rockets have been fired from Gaza toward Israel, according to the Israel Defence Forces.
Hamas official takes credit for kidnap, murder of Israeli teens
PHOTOS: Balloons, ice creams, siesta amid Israel-Hamas war
Explaining India's UN vote on Israel
Israel loses its heroic sheen
Obama signs funding package for Israel's Iron Dome