London, Jan 11 (ANI): The mastermind of Hamass long-range rocket attacks on Israel was killed yesterday in an airstrike, Israeli military sources have said.

Amir Mansi, an engineer who commanded cells responsible for firing Grad rockets supplied by Iran, died after coming under attack from a helicopter, The Times reported.

The Israeli army said he had been trying to fire mortar shells at their troops when he was targeted.

Mansi headed the Hamas military wings Gaza Strip rocket division and played a big role in Grad rocket attacks on Israeli communities, a military spokesman said.

He was killed after a Grad struck the Israeli town of Gedera, near the Tel Nof airbase, where nuclear weapons are believed to be stored, the paper said.

His death was disclosed as Israeli forces said they had surrounded Gaza City, putting nearly one million Palestinians under siege. Leaflets dropped by air warned that the 15-day-old offensive would be escalated.

More than 800 Palestinians and 13 Israelis have died in the conflict. Nine people, including two children, were killed in a Gaza garden on Saturday.

A 20,000-strong protest in central London ended in clashes with police last night.

Three officers were injured after coming under sustained attack near the Israeli embassy from protesters armed with baseball bats and placards, The Times reported. (ANI)