Palestinians look on during a search for casualties at the site of Israeli strikes on houses in Khan Younis on Wednesday. Reuters

Israel's military intensified its bombing of southern Gaza overnight after one of the deadliest days for Palestinians since the conflict began as world leaders called for a halt to fighting to allow aid into the besieged enclave.

Amid concerns the Israel-Hamas conflict will spread across the Middle East, Israel's military said its jets struck Syrian army infrastructure and mortar launchers in response to rockets launched from Iran ally Syria.

The military did not provide further details. It did not accuse Syria's army of firing the two rockets, which set off air raid sirens in the Israeli-occupied Golan Heights.

Citing a military source, Syrian state news agency (SANA) said the Israeli attack killed 8 soldiers and wounded 7 more in an "aerial aggression" near the southwestern city of Deraa.

The United States and Russia are leading international calls for a pause in fighting between Israel and Hamas to allow aid into Gaza where Palestinians are living in harrowing conditions.

A total of 704 Palestinians, including 305 children, were killed on Tuesday, the health ministry in Hamas-ruled Gaza said, a toll the UN Office for the Coordination of Humanitarian Affairs said was the highest reported in a single day since the conflict began nearly three weeks ago.

People stand near the bodies of Palestinians killed in overnight Israeli bombardment. AFP

Israel launched the strikes on Gaza after Hamas attacked southern Israeli towns on Oct. 7 in a rampage that killed 1,400 people, most of them civilians.

Israel has responded with withering air strikes and a near-total land, sea and air blockade of Gaza, where the Hamas-run health ministry says 5,791 people have been killed in the war so far.

US President Joe Biden and Saudi Arabian Crown Prince Mohammed Bin Salman spoke by phone on Tuesday and agreed on broader diplomacy "to maintain stability across the region and prevent the conflict from expanding," the White House said.

A child who was injured in Israeli bombardment is carried to a hospital for treatment in Khan Yunis. AFP

Deadly clashes have intensified between the Israeli military and Palestinians in the occupied West Bank, and resurged between Israel and Lebanon's Hezbollah armed group along the Israeli-Lebanon border.

Iran, which has sought regional ascendancy for decades, backs both Hezbollah and Hamas, and has warned Israel to stop its onslaught on Gaza.

Israeli forces on an overnight raid in the occupied West Bank came under fire from a group of Palestinians whom the military then hit with a drone, the Israeli military said. Palestinian officials said three people were killed.

Since Oct.7, more than 100 Palestinians have been killed in West Bank clashes with the Israeli military, the Palestinian Health Ministry said.

A medic helps a child wounded in the Israeli bombardment of the Gaza Strip in Deir Al-Balah hospital on Tuesday. AP

Israel's military also said it targeted a cell of Hamas divers attempting to enter Israel by sea near Kibbutz Zikim. There was no immediate comment from Hamas on the incident.

The US has advised Israel to hold off on a planned ground assault as Washington tries to free more of the 200-plus hostages Hamas is still holding captive in Gaza.

Agencies