Cairo: Israeli military strikes across the Gaza Strip killed at least 65 Palestinians overnight, including in a school sheltering displaced families, medics said, as Israeli tanks advanced in areas of Khan Younis in the south of the enclave.

Israeli tanks carried out a raid on several areas in eastern and central Khan Younis in the southern Gaza Strip before partially retreating, leaving at least 40 people killed and dozens wounded, according to the official Voice of Palestine radio and Hamas media.

In Gaza City, at least 22 Palestinians were killed, the medics said. One Israeli strike on a school sheltering displaced families in Gaza City killed 17 people, while another hit the Al-Amal Orphan Society, which also houses displaced persons, killing at least five others, the medics said.

Later on Wednesday, an Israeli strike on a school sheltering Palestinian displaced families in Nuseirat in central Gaza killed three people and wounded 15, medics said. The Israeli military said the strike was aimed at Hamas militants operating from a command centre embedded in the compound that had previously served as the 'Nuseirat Girls' School.

It accused Hamas of exploiting civilian facilities and population for military purposes, a tactic Hamas denies using.

The escalation came after Iran launched a salvo of ballistic missiles at Israel on Tuesday in retaliation for Israel's campaign against Tehran's Hezbollah allies in Lebanon, and Israel vowed a "painful response" against its enemy.

Palestinians in the Gaza Strip, locked in nearly a year of war with Israel, celebrated as they watched dozens of rockets en route to Israel. Some of those rockets fell in the Palestinian enclave after being intercepted by Israel's Iron Dome missile defences but caused no human losses, witnesses said.

Hezbollah began firing rockets into Israel almost a year ago in support of its ally Hamas in the war in Gaza, which started after the militant group staged the deadliest assault in Israel's history on October 7.

The assault, in which Israel says 1,200 people were killed and more than 250 taken hostage, triggered the war that has devastated Gaza, displacing most of its 2.3 million population and killing more than 41,600 people, according to Gaza health authorities.