Hostilities between Israel and Hamas escalated overnight, with at least 35 killed in Gaza and five in Israel in the most intensive aerial exchanges for years.
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.
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.
It was the heaviest fighting between the bitter enemies since 2014, and it showed no signs of slowing.
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.
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.
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.