Relentless rocket fire and rioting in mixed Jewish-Arab towns fuelled growing fears Wednesday that violence between Israel and Palestinians that has claimed 50 lives could spiral into "full-scale war".
Palestinian militants have launched more than 1,000 rockets since Monday, said Israel's army, which has launched hundreds of air strikes on Hamas and other Islamist groups in the crowded costal enclave of Gaza.
The most intense hostilities in seven years have killed at least 43 people in Gaza, including 13 children, two Palestinians in the West Bank, and five Israelis, triggered by weekend unrest at Jerusalem's Al-Aqsa mosque compound, which is sacred to both Muslims and Jews.
As world powers voiced growing alarm and the UN Security Council readied for another emergency meeting on the bloody crisis, the UN Middle East envoy Tor Wennesland warned that "we're escalating towards a full-scale war".
"Leaders on all sides have to take the responsibility of de-escalation," he said, echoing warnings from the international community.
Israeli Prime Minister Benjamin Netanyahu declared a state of emergency in the mixed Jewish-Arab Israeli city of Lod, where police said "wide-scale riots erupted among some of the Arab residents".
There were fears of widening civil unrest as protesters waving Palestinian flags burnt cars and properties, clashed with Israeli police and attacked Jewish motorists in several mixed Jewish-Arab towns across Israel.
Palestinian groups, mostly Hamas and Islamic Jihad, have launched more than 1,000 rockets, Israel's army said, including hundreds at Tel Aviv, where air sirens wailed overnight.
Of these, 850 rockets have hit in Israel or been intercepted by Israel's Iron Dome air defence system, while the rest have crashed inside Gaza, he said.
Israel has launched hundreds of air strikes at Gaza, the Israeli-blockaded coastal enclave of two million people that Hamas controls, targeting what the army described as Palestinian military sites.
Aside from the mounting death toll, at least 230 Palestinians were wounded, many rescued from the smouldering ruins of buildings. On the Israeli side, more than 100 people have been injured, as residents across the Jewish state have been ordered to seek shelter.
British Prime Minister Boris Johnson on Wednesday urged Israel and the Palestinians to "step back from the brink", calling for both sides to "show restraint".