Israeli F16 warplanes struck on Thursday evening a 3-story building in northern Gaza City killing five, including three senior leaders of Islamic Resistance Movement (Hamas), local medical sources said.

Paramedics told local radio stations that Hamas Interior Minister Said Siam, the head of its security apparatus, Salah Abu Shreh, and the head of its military wing, Mahmoud Watfah were killed in the airstrike.

Siam's brother and son were also killed in the attack, with more than 30 wounded, medical sources added.

Witnesses said that an Israeli F16 warplane fired two rockets at the building belonging to the brother of Said Siam in al-Yarmook Street in northern Gaza City, adding that the building was completely destroyed.

Siam, No.3 behind Ismail Haneya and Mahmoud Zahar in Hamas leadership and the effective founder of the Hamas-led police force, was viewed as the most extreme of the three leaders.

Meanwhile, the Israeli army warplanes and tanks continued carrying out airstrikes and shelling of different targets all over the Gaza Strip, focusing on Gaza City with around 700,000 population.

Gaza emergency chief Mo'aweya Hassanein said that since the beginning of the offensive three weeks ago, Israeli army have killed 1,077 Palestinians and wounded more than 5,000, adding that almost half of the casualties are civilians.

He said that more than 25 Palestinians were killed on Thursday and dozens were injured, adding that many houses and properties were destroyed in the southern Gaza City neighborhood of Tal el-Hawa.