Smoke billows into the sky after an Israeli airstrike on the Hanadi compound in Gaza City. AFP
Relentless rocket fire and rioting in mixed Jewish-Arab towns fuelled growing fears on Wednesday that violence between Israel and Palestinians that has claimed 55 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 in the crowded costal enclave of Gaza.
The most intense hostilities in seven years have killed at least 48 people in Gaza, including 14 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.
Israeli air strikes kill more Palestinians
UN deeply concerned at escalation in Israeli-Palestinian violence
It says nearly 300 Palestinians in the territory have been wounded in the strikes, which began on Monday as Palestinians launched a barrage of rockets into Israel.
Israel stepped up its attacks on the Gaza Strip, flattening a high-rise building on Tuesday as Palestinian rockets rained down almost nonstop on parts of Israel, according to AFP.
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.
Israel carried out hundreds of air strikes in Gaza into the early hours of Wednesday, as the Palestinian groups fired multiple rocket barrages at Tel Aviv and Beersheba.
The worst fighting since the 2014 Gaza war was ignited by clashes in Jerusalem in recent weeks between Palestinian protesters and Israeli police focused on the Al-Aqsa Mosque compound, a site sacred to Jews and Muslims.
Israeli security forces take up positions amid clashes with demonstrators in the occupied West Bank. AFP
Israeli Prime Minister Benjamin Netanyahu vowed to expand the offensive, while Palestinians unleashed a fierce late-night barrage of rockets that set off air-raid sirens and explosions throughout the densely populated Tel Aviv metropolitan area.
One multi-story residential building in Gaza collapsed and another was heavily damaged after they were repeatedly hit by Israeli air strikes.
Israel said its jets had targeted and killed several Hamas intelligence leaders early on Wednesday. Other strikes targeted what the military said were rocket launch sites and Hamas offices.
It was the heaviest offensive between Israel and Hamas since a 2014 war in Gaza, and prompted international concern that the situation could spiral out of control.
Just after daybreak Wednesday, Israel unleashed dozens of airstrikes in the course of a few minutes, targeting police and security installations, witnesses said. A wall of dark gray smoke rose over Gaza City.
A Palestinian woman walks past a damaged house in the aftermath of Israeli airstrikes in Gaza. Reuters
Five Israelis, including three women and a child, were killed by rocket fire on Tuesday and early on Wednesday, and dozens of people wounded. The death toll in Gaza rose to 35 Palestinians, including 10 children, according to the Health Ministry. Over 200 people were wounded.
In the West Bank, meanwhile, a 26-year-old Palestinian was killed during clashes with Israeli troops that entered Al Fawar refugee camp in southern Hebron, the ministry said.
A Palestinian woman carrying her son runs for cover after their tower building was hit by Israeli airstrikes in Gaza. Reuters
In another sign of widening unrest, demonstrations erupted in Arab communities across Israel, where protesters set dozens of vehicles on fire in confrontations with police.
The fighting between Israel and Hamas was the most intense since a 50-day war in the summer of 2014. In just over 24 hours, the current round of violence, sparked by religious tensions in the contested city of Jerusalem, increasingly resembled that devastating war.
Palestinians across Israel and the occupied territories went on strike in a rare collective action against Israel's policies on Tuesday as Israeli strikes rained down on Gaza and Hamas group fired dozens of rockets from the Hamas-ruled territory.
In renewed airstrikes on Thursday, Israel destroyed a six-storey residential building in the heart of Gaza City. One man was killed by an Israeli missile fired east of Khan Younis in southern Gaza, medics said.
The Health Ministry said the latest airstrikes left at least two dead and 25 wounded, including children and women. It said rescuers are still digging through the rubble and had so far pulled up five more wounded.
During the meeting, they reviewed the ties between the two friendly countries across various domains and ways of enhancing them to achieve their common interests.
The impoverished Central Asian country with ties to Russia and China has seen three presidents resign over political crises fuelled by corruption, nepotism and disputed votes since gaining independence from the Soviet Union in 1991.
Sheikh Mansour Bin Zayed Al Nahyan also sent congratulatory messages to the King of Sweden and to the Prime Minister Ulf Kristersson.