Hezbollah said on Saturday it had launched dozens of Katyusha rockets at Israel, the latest in a series of attacks it says is in support of the Palestinian people.

The Lebanese group said its latest attack, on Beit Hillel in northern Israel, was in response to Israel's attacks on Kfar Kela and Deir Siriane in Lebanon which, it said, had injured civilians there.

Meanwhile, Middle East tensions soared on Saturday as Iran and its allies readied their response to the assassination of Hamas's political leader, blamed on Israel, spurring fears of a regional war.

Israel ally the United States said it would move warships and fighter jets to the region, while Western governments called on their citizens to leave Lebanon -- where the powerful Iran-backed Hezbollah movement is based -- and airlines cancelled flights.

The killing this week of Hamas leader Ismail Haniyeh in Tehran, hours after the Israeli assassination of Hezbollah's military chief in Beirut, has triggered vows of vengeance from Iran and the so-called "axis of resistance".

Iran-backed groups from Lebanon, Yemen, Iraq and Syria have already been drawn into the nearly 10-month war between Israel and Palestinian militant group Hamas in Gaza.

Israel on Saturday again traded fire with Hezbollah, carried out a deadly raid in the occupied West Bank, and struck a school compound in Gaza City in an attack that the Hamas-ruled territory's civil defence agency said killed at least 17 people.

Numerous schools turned into displacement shelters have been hit across Gaza in recent weeks, with Israel insisting the facilities had been used by militants. Hamas denied using civilian infrastructure for military activities.

Haniyeh was buried on Friday in Qatar, where he had been based. Israel, accused by Hamas, Iran and others of carrying out the attack, has not directly commented on it.

Iran said on Saturday it expects Hezbollah to hit deeper inside Israel and no longer be confined to military targets.

The Pentagon said it was bolstering its military presence in the Middle East to protect US personnel and defend Israel.

It said an aircraft carrier strike group led by the USS Abraham Lincoln would be deployed, as well as additional ballistic missile defence-capable cruisers and destroyers and a new fighter squadron.

US President Joe Biden, at his beach home in Delaware, was asked by reporters if he thought Iran would stand down.

"I hope so," he said. "I don't know."

Soon after, Hezbollah announced it had fired dozens of Katyusha rockets at the northern Israeli settlement of Beit Hillel.

They said it was in response to an Israeli attack on Kfar Kela and Deir Siriane in southern Lebanon which, it said, had injured civilians.

Earlier on Saturday, Hezbollah announced the deaths of two of its fighters, including a 17-year-old from Deir Siriane. (AFP)