Palestinian militants fired a barrage of rockets at Israel’s economic hub Tel Aviv on Tuesday in retaliation for an Israeli strike that destroyed a tower block in Gaza, as the foes traded their heaviest fire for several years.

The sharp escalation, triggered by violence in Jerusalem, has killed at least 32 Palestinians in the blockaded Gaza Strip and three Israelis, and wounded hundreds more.

“This is just the beginning” of Israel’s strikes, Minister Benny Gantz warned.

Hamas leader Ismail Haniyeh vowed that “if Israel wants to escalate, we are ready for it.”

The UN envoy for Middle East Peace, Tor Wennesland, warned that Israel and Hamas were “escalating towards a full-scale war”.

In the crowded, Israeli-blockaded enclave of Gaza that Hamas controls, 10 children and one woman were among those killed since Monday night.

A further 220 people were reported wounded from the ongoing Israeli air strikes, many rescued from the smouldering ruins of buildings.

In Israel, sirens sounded as Hamas rockets rained down, and some of those unable to make it to underground shelters took cover under bridges.

“It was scary,” said Haim Roy Ben Shlomo, 38, resident of Ramat Gan near Tel Aviv, adding he had heard “several loud shots, or booms, above our heads.”

An Israeli woman was killed as rockets hit Rishon Letzion on the coastal city’s southern edge, while in nearby Holon, AFP footage showed a burnt-out bus as rescue workers cleaned up debris.

The rocket fire forced Israel to suspend flights at its main airport of Ben Gurion, near Tel Aviv.

Israeli Prime Minister declared a state of emergency in the central city of Lod which borders the airport, as police said “wide-scale riots erupted by some of the Arab

residents”.

Reinforcements were sent to the area after clashes broke out the night after an Israeli Arab was killed in the city.

In Gaza, people sifted through debris after an Israeli air strike destroyed a 12-storey building.

Hamas, which controls the Palestinian territory, said the tower block had been a residential building. AFP reporters said it also houses offices of several Hamas officials.

Hamas and the Islamic Jihad group confirmed they had commanders who had died in the Israeli strikes.

Hamas threatened to turn the nearby Israeli city of Ashkelon into “hell”, and rockets fired by militants in Gaza killed two women there.

At one stage the group claimed to have fired more than 100 rockets in under five minutes to overwhelm air defences.

The armed branch of Hamas later said it had fired more than 200 rockets. Israel’s said more than 600 rockets had been fired since Monday from Gaza towards Israel mainly by Hamas and the Islamic Jihad group.

Many landed inside Gaza or were taken out by Israel’s Iron Dome air defence system, but at least 100 Israelis were injured.