Israel today launched fresh offesive against Hamas in Gaza, killing at least five Palestinians, even as the militant group publicly executed 18 suspected spies for the Jewish state following the killing of its three top commanders.

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 shot seven more Palestinians in front of hundreds of people in a central Gaza square, witnesses said.

Hamas warned the same punishment will be imposed soon on others. The executions came a day after Israel killed three top Hamas commanders - Mohammed Abu Shamala, Mohammed Barhoum and Raed al-Attar who were key to Hamas operations including smuggling, tunnel construction and also played a role in capturing Israeli soldier Gilad Shalit in 2006.

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 rules Gaza, has warned that Israel will "pay the price" for killing the high-ranking leaders of its military wing, the Qassam Brigades.