Hostilities between Israel and Hamas escalated on Tuesday, raising the death toll in two days to 32 Palestinians and three people in Israel, with Israel carrying out multiple airstrikes in Gaza and the militant group firing rockets at Tel Aviv.

Into the early hours of Wednesday morning, Gazans reported their homes shaking and the sky lighting up with Israeli attacks, outgoing rockets fired by Hamas and Islamic Jihad, and Israeli air defence missiles intercepting them.

A 13-story residential building in Gaza collapsed after it was hit by an Israeli airstrike, one of hundreds that Israel said it had carried out against Hamas targets.

They were the most intensive aerial exchanges between Israel and Hamas since a 2014 war in Gaza, and prompted international concern that the situation could spiral out of control.

U.N. Middle East peace envoy Tor Wennesland tweeted: "Stop the fire immediately. We're escalating towards a full-scale war. Leaders on all sides have to take responsibility for de-escalation.

"The cost of war in Gaza is devastating & is being paid by ordinary people. UN is working w/ all sides to restore calm. Stop the violence now," he wrote.

Israelis ran for shelters or flattened themselves on pavements in communities more than 70 km (45 miles) up the coast amid sounds of explosions as interceptor missiles streaked into the sky. Israel said hundreds of rockets had been fired by Palestinian militant groups.

Global concern: India COVID variant found in 44 countries, says WHO

WHO didn't use the word 'Indian' in a corona variant: Govt of India

Bangladesh aircraft carrying China-contributed vaccines reaches Dhaka