Smoke trails are seen as an Iron Dome intercepts a rocket which was launched from Gaza, near Sderot Reuters

A four-year-old Israeli boy has been killed by a mortar fired from the Gaza Strip, medical officials have confirmed.

The child was killed in a village in southern Israel, close to the border with the Gaza Strip.

Eli Bin, the head of Israel's national rescue service, confirmed the death in TV interviews.

Rocket sirens were heard across central Israel as two rockets were intercepted over the city of Tel Aviv.

The death is the first since fighting between Palestinian factions and Israel resumed following the collapse of a temporary ceasefire earlier in the week.

In the six-week conflict, over 2,000 Palestinians - mostly civilians - and 68 Israelis - all but three were soldiers - have been killed.

Elsewhere, the armed wing of Hamas, al-Qassam Brigades, has executed 18 Palestinians who were accused of collaborating with Israel during the Gaza war.

Under Palestinian law, being an Israeli informer is punishable by death. In May, Hamas announced the execution of two men accused of being collaborators.

The killings, which reportedly took place in Gaza City Police HQ, came after Israel Defense Forces (IDF) killed three senior Hamas commanders - Raed al-Attar, Mohammed Abu Shammala and Osama Abu Atah - in air strikes on Rafah, southern Gaza Strip.