Israel has deployed tanks and troops to its border with Gaza, as it mulls whether to launch a ground operation in the territory after days of violence.
Conflict raged throughout Thursday as Palestinian militants fired rockets into Israel and the Israeli army maintained a barrage of air strikes.
More than 100 people have been killed in Gaza and seven have died in Israel.
Jewish and Israeli Arab mobs have also been fighting within Israel, prompting the president to warn of civil war.
Defence Minister Benny Gantz ordered a “massive reinforcement” of security forces to suppress the internal unrest, and more than 400 people were arrested.
Two infantry units and one armoured unit were positioned near the border with Gaza on Thursday. At least 7,000 army reservists have also been called up.