Israel and militants in the Gaza Strip have stepped up their attacks on each other, in some of the most intense exchanges of recent years.
The army says Palestinian militants have fired 600 rockets into Israeli territory over the weekend, leaving four Israelis dead.
Israel says it has hit 280 targets in the Gaza Strip and threatened further “massive” strikes.
At least 15 people have died so far in Gaza, the Health Ministry there says.
On Sunday, Israeli Prime Minister Benjamin Netanyahu said he had ordered the military to “continue its massive strikes on terror elements in the Gaza Strip”.
Israeli forces around Gaza would be “stepped up with tank, artillery and infantry forces”, he added.
The flare-up comes despite a truce agreed last month. Egypt and the United Nations have recently been trying to broker a longer-term ceasefire.
UN Secretary-General Antonio Guterres has appealed for “maximum restraint”.
