The deadly exchange of fire between Palestinian militants in the Gaza Strip and the Israeli military has escalated significantly, with the UN fearing a “full-scale war”.
More than 1,000 rockets have now been fired by Palestinian militants over 38 hours, Israel said, most at Tel Aviv.
Israel has carried out deadly airstrikes, bringing down two tower blocks in Gaza on Tuesday.
Israeli Arabs have also staged violent protests in a number of Israeli towns.
The city of Lod, near Tel Aviv, has been put under a state of emergency.
UN Secretary-General António Guterres said he was “gravely concerned” by the ongoing violence.
Six Israelis and at least 35 Palestinians, including 12 children, have been killed since Monday.
The fighting follows weeks of rising tension stoked by violent confrontations between Israeli police and Palestinian protesters at a site in Jerusalem that is holy to both Muslims and Jews.
Israel’s military says this is the biggest exchange since 2014.