Israel bombed the Gaza Strip where one hospital reported at least 30 dead Friday and as exchanges of fire and threats over the Lebanon border raised fears of an even wider war.

After further cross-border fire between Israel and Lebanon's powerful Hezbollah movement, UN Secretary-General Antonio Guterres warned the clashes must not turn Lebanon into "another Gaza".

Increased "bellicose rhetoric" from both sides risked triggering a catastrophe "beyond imagination", he said.

In Gaza the director of Gaza City's Al-Ahli hospital was quoted by the Hamas-run territory's health ministry as reporting 30 dead on Friday in intensified Israeli bombardment.

"It has been a difficult and brutal day in Gaza City. So far, around 30 martyrs have arrived at the Al-Ahli Arab Hospital," Dr Fadel Naeem was quoted as saying.

Civil defence agency spokesman Mahmud Basal said five municipal workers died when a garage in the city was bombed.

Israel's military reported military operations on Friday "north and south of the Central Gaza Strip Corridor".

AFPTV captured an overnight strike on Khan Yunis city, showing a ball of fire and sparks erupting in a residential district.

Just before midnight Thursday, Israel's army said it had "successfully intercepted a suspicious aerial target that crossed from Lebanon".

Early Friday, Lebanese official media reported new Israeli strikes in the south.

They came after Hezbollah said it had fired dozens of rockets at a barracks in northern Israel on Thursday in retaliation for a deadly air strike in south Lebanon.

Israel said a Hezbollah operative was killed in that strike.

It said jets struck Hezbollah sites and used artillery "to remove threats in multiple areas in southern Lebanon".

Hezbollah claimed a number of attacks on Israeli troops and positions near the border on Friday, including two using drones.

Experts are divided on the prospect of a wider war, almost nine months into Israel's campaign to eradicate Iran-backed Hezbollah's ally Hamas, the Palestinian militant group in the Gaza Strip.

Exchanges between Hezbollah and Israel have escalated, and Israel's military said on Tuesday plans for an offensive in Lebanon "were approved and validated".

Hezbollah chief Hassan Nasrallah said "no place" in Israel would "be spared our rockets" in a wider war, and also threatened nearby European Union member Cyprus.

Israel's ally the United States has appealed for de-escalation.

Two soldiers killed

The violence on the Lebanon border began after the October 7 attack by Hamas militants from Gaza into southern Israel. That attack resulted in the deaths of 1,194 people, mostly civilians, according to an AFP tally based on Israeli official figures.

The militants also seized hostages, 116 of whom remain in Gaza although the army says 41 are dead.

Israel's retaliatory offensive has killed at least 37,431 people, also mostly civilians, according to Gaza's health ministry.

Months of negotiations towards a truce and a hostage release have failed to make headway, but mediator Qatar insisted Friday it was still working to "bridge the gap" between Israel and Hamas.

The war has destroyed much of Gaza's infrastructure and left residents short of food, fuel and other essentials.

On June 16 the army said it would implement a daily "tactical pause of military activity" in a southern Gaza corridor to facilitate aid delivery.

But on Friday Richard Peeperkorn of the World Health Organization said "we did not see an impact on the humanitarian supplies coming in".

Hisham Salem in Jabalia camp told AFP: "The markets... used to be full, but now there is nothing left. I go around the entire market and I can't find a kilo of onions, and if I do... it costs 140 shekels ($37)."

Dr Thanos Gargavanis, a WHO trauma surgeon and emergency officer, said the UN in Gaza was trying to "operate in an unworkable environment".

According to the WHO, only 17 of the 36 hospitals in Gaza are operational, but only partially.

It said that as of May 17, just 750 people remained in Rafah city where previously 1.4 million people had been sheltering.

Israel's military on Friday identified two more soldiers killed in Gaza, bringing to at least 312 killed since ground operations began.

Israeli Prime Minister Benjamin Netanyahu, who is on trial for corruption charges which he denies, faces regular street protests accusing him of prolonging the war, and demanding an agreement to free the hostages.

Vexing' comments

But Netanyahu told relatives of captives killed in Gaza: "We will not leave the Gaza Strip until all of the hostages return."

On Thursday he said he was "prepared to suffer personal attacks provided that Israel receives the ammunition from the US that it needs in the war for its existence".

His statement came as an apparent doubling down after he made a video statement accusing Washington of "withholding weapons and ammunitions to Israel".

The White House on Thursday described his comments as "vexing" and "disappointing".

Except for one shipment, "there are no other pauses. None," press secretary Karine Jean-Pierre said, referring to one paused delivery of 2,000-pound (907-kilo) bombs.

The war has revived a global push for Palestinians to be given a state of their own.

Armenia on Friday declared its recognition of "the State of Palestine", prompting Israel to summon its ambassador for "a severe reprimand".