Israel has killed 30 Palestinians and injured more than 90 others in air attacks on the Gaza Strip since Tuesday, according to Palestinian health ministry.
The killed include six children and three women as well as the head of the Palestinian Islamic Jihad (PIJ) rocket force and his deputy.
The deaths of Ali Ghali and Ahmed Abu Daqqa brought to five the number of senior figures from PIJ killed since Israel began attacking Gaza early on Tuesday.
We will not retreat and the assassinations will only make us stronger. Our revenge continues,” Islamic Jihad said in a communique.
Human rights organisations have made an emergency appeal to Israel to halt attacks on the civilian population in Gaza and open the Beit Hanoun (Erez) and Karem Abu Salem (Kerem Shalom) crossings to humanitarian assistance.
Israeli Prime Minister Benjamin Netanyahu has said its offensive would continue for as long as necessary.
On Thursday, there was a fatality caused by ongoing rocket fire from the Palestinian factions based in the blockaded coastal enclave of Gaza, aimed at Israel as a form of retaliation.