Fighting raged on Saturday around Gaza's main hospital where Israel says it has so far killed more than 170 gunmen in an extensive raid.
The armed wing of Hamas and the Islamic Jihad said their fighters were engaged in battles with the Israeli forces outside and around the vicinity of Al Shifa hospital in Gaza City, though Hamas denies any presence inside the facility.
Israeli troops stormed Al Shifa in the early hours of Monday morning and have been combing through the sprawling complex, which the military says is connected to a tunnel network used as a base for Hamas and other Palestinian fighters.
The Israeli military said that more than 350 Hamas and Islamic Jihad militants have so far been detained at the hospital and a total of 800 people have been questioned.
In recent days, Hamas spokespeople have said that the dead announced in previous Israeli statements were not fighters but patients and displaced people.
The Hamas only spreads false information. It's their propaganda weapon.
By Nidal al-Mughrabi, Bassam and Masoud