Two Lebanese soldiers killed in Israeli airstrike hours after UN peacekeepers HQ fired on

An Israeli airstrike has killed two Lebanese soldiers and wounded three others, hours after the Israeli military fired on the headquarters of a UN peacekeeping mission in Lebanon for the second time in as many days.

The two incidents on Friday prompted further concern over Israel’s escalating campaign, amid waves of heavy airstrikes across Lebanon. Lebanon’s army has not been involved in the fighting between Israel and Hezbollah, and it withdrew its forces from the border between the countries when Israel launched its invasion last month.

The Lebanese army said its soldiers died in an Israeli airstrike near a military checkpoint in the southern Bint Jbeil province. The Israel Defense Forces (IDF) said that it had been targeting Hezbollah positions and was “unaware of any Lebanese army facilities found in the area of the strike”.

That airstrike came soon after two Sri Lankan members of the UN Interim Force in Lebanon (Unifil) were injured when the IDF opened fire near the peacekeeper’s base in Naqoura. The Israeli army said that its soldiers had targeted what they believed to be a threat 50 metres from the base, adding that it would continue to “examine the circumstances of the incident”.

Late on Friday night, Hezbollah warned Israelis to stay away from army sites in residential areas in the north of the country, saying Israel “uses the homes of settlers in some settlements”, and has military bases “inside settlement neighbourhoods.

“We warn the settlers from being near these military gatherings in order to preserve their lives.”

The shelling of UN positions has come as the conflict, which began a year ago in Gaza, continues to spread. Overnight Israeli airstrikes on central Beirut killed 22 people when they hit a densely populated residential neighbourhood of apartment blocks and small shops in the heart of the Lebanese capital.

Related: US-made munition used in Israeli strike on central Beirut, shrapnel shows

Gaza’s civil defence agency said on Friday that at least 30 people were killed by Israeli strikes throughout the day in northern Gaza’s Jabaliya town and refugee camp.

At least 12 people were killed, including women and children, by a strike that occurred before 9.40pm local time (7.40pm BST), according to the agency. Before that incident, the director of the agency said 18 people had been killed by several Israeli strikes, including hits on eight schools in Jabaliya camp that were serving as shelters for displaced people.

The health ministry in Gaza said on Friday that at least 42,126 Palestinians had been killed by the Israeli military in the territory since the war, 61 of them in the most recent 24-hour period. The conflict was triggered on 7 October by a Hamas raid into southern Israel, in which its militants killed 1,200 Israelis and took 250 hostage.

The Unifil statement issued on Friday pointed out that the UN security council had sent peacekeepers to Lebanon in 2006 as part of arrangements that ended the last Israel-Hezbollah war , and the multilateral force had been exposed to “very serious risks”.

Two Indonesian Unifil peacekeepers were lightly wounded on Thursday when they were thrown from an observation tower that was hit by an Israeli tank round, and two other Unifil outposts had come under fire.

Joe Biden, the US president, said he was asking Israel to not hit UN peacekeepers, and the UN secretary general, António Guterres, told Israel that attacks on the peacekeeping force were intolerable.

Lt Col Nadav Shoshani, an IDF spokesperson, said on Friday the force was looking into the cases of UN peacekeepers being “inadvertently hurt during IDF combat”.

“The IDF expresses deep concern over incidents of this kind and is currently conducting a thorough review at the highest levels of command,” he said.

Unifil’s spokesperson, Andrea Tenenti, said the attacks on the UN bases had impaired the peacekeepers’ ability to monitor the conflict in southern Lebanon and ground incursions by IDF units.

“We have not been able to monitor the area as much as we want to because, for the safety and security of our troops, it’s important to stay inside the bases,” he told CNN in India.

He said 350,000 of the 500,000 people who live in southern Lebanon had fled their homes since the fighting started.

“We’re trying to do whatever we can to assist and to provide humanitarian assistance,” Tenenti said. “But the security concerns are very high.”

Philippe Lazzarini, the head of the UN relief organisation for Palestinian refugees across the region (Unrwa), said people in Gaza had become accustomed to being moved about “like pinballs” by IDF operations . He feared that the people of southern Lebanon were facing the same plight.

Related: ‘It felt like death was chasing us’: one Gaza family’s attempt to evade Israeli strikes – visualised

“One of the fears is that we replicate a situation similar to the one we have seen until now in Gaza,” he said.

The Israeli shelling of UN positions marks the culmination of a downward spiral of Israel’s relations with the international body. The Israeli foreign minister, Israel Katz, declared Guterres persona non grata earlier this month, accusing him of “lending support to terrorists” after the secretary general’s calls for a ceasefire in Gaza.

Speaking at an Asian summit in Laos on Friday, Guterres said the spread of the Middle East conflict would have dramatic effects on the world.

“I have never seen in my time as secretary general any example of death and destruction as dramatic as what we are witnessing here,” he said. “We are seeing escalation after escalation, a regionalisation of the conflict that is becoming a threat to global peace and security.”

The incidents at Unifil positions drew outrage from countries that contribute soldiers to serve as peacekeepers.

Spain’s prime minister, Pedro Sánchez, condemned the attacks and called on the international community to stop selling weapons to Israel. The French foreign ministry summoned Israel’s ambassador over an incident in which Israeli troops opened fire at three positions held by UN peacekeepers.

Human Rights Watch called for the UN to set up a formal inquiry into Israeli attacks on Unifil peacekeepers, pointing out they could violate the laws of war.