The Israel-Hamas war that has spilled into Lebanon intensified on Thursday as a UN peacekeeping mission said that it was fired on by Israeli forces, while a senior Hezbollah official reportedly avoided an assassination attempt in the country.

The United Nations' peacekeeping force in Lebanon, UNIFIL, said two of its personnel were injured when an Israeli tank fired at a watchtower on Thursday at the force's main headquarters in Ras al-Naqoura, hitting the tower and causing the peacekeepers to fall. There were no casualties, a UN source said.

"This is highly concerning, not only because the peacekeepers are there, but because this was done by, you know, most probably a deliberate attack against our troops, which is a violation or a grave violation of international humanitarian law," UNIFIL spokesperson Andrea Tenenti said.

Fu Cong, China's permanent representative to the United Nations, voiced "grave concerns" about the situation in Lebanon at a UN Security Council briefing Thursday.

"Recent weeks have witnessed a sharp rise in tensions between Lebanon and Israel. A few hours ago, the IDF attacked UNIFIL positions and an observation tower, causing injuries to UNIFIL personnel," he said.

"China expresses grave concerns and strong condemnation. UNIFIL carries out its peacekeeping tasks under the mandate from the Security Council resolution. Any deliberate attacks on peacekeepers constitute a severe violation of international humanitarian law and Security Council Resolution 1701. Such acts must stop immediately.

"We demand that these attacks be investigated and those responsible be held to account. Measures must be taken to prevent any reoccurrence," Fu said. "We reiterate that all parties to the conflict must effectively guarantee the safety and security of all UN personnel and assets, including UNIFIL."

Fu said that "the gravity of the current situation is clear, as is the right direction to de-escalation" as he detailed three points of emphasis:

"First, since October last year, the series of destabilizing events that have taken place in the Middle East have resulted in more than 100,000 civilian casualties and left millions of people displaced. The cleanup work will take a decade or so," Fu said. "What's more, the trauma brought by conflicts will be a lingering nightmare for generations to come. The Middle East cannot afford a full-scale war. The conflict cannot continue to expand.

"All parties must keep in mind the interest of maintaining regional peace and stability, deal with the current situation in a calm, rational, and responsible manner, and make sincere efforts towards breaking the cycle of violence," he said.?

"Second, achieving a cease-fire must be an overarching priority. We note that all parties in Lebanon have already made a unanimous call for an immediate cease-fire," he said. "The Arab League has also issued an explicit appeal. It is clear who holds the key to ending this crisis. We urge Israel to set aside its obsession with the use of force, make the right political decision, stop violating Lebanon's sovereignty and territory integrity, and end its adventurous behavior that could drag the region into a new catastrophe.?

Finally, Fu said: "Third, there is no time to lose for the council to act. The vast majority?of council members have long since reached a broad consensus on deescalating the conflict, achieving a cease-fire, stopping the violence and seeking a diplomatic solution.

"We urge a certain country to stop its passive procrastination, cover-up, and connivance. Instead, it should act responsibly and play a constructive role in order to prevent further destabilization of the situation," he said.?

The White House said the United States was deeply concerned by reports that Israeli forces fired on UN positions and was pressing Israel for details.

Israel's military said in a statement its troops operated in the Naqoura area, "next to a UNIFIL base".

"Accordingly, the IDF instructed the UN forces in the area to remain in protected spaces, following which the forces opened fire in the area," Israel's statement said, adding that it maintains routine communication with UNIFIL.

In New York, Israel's UN Ambassador Danny Danon said the country was focused on fighting Hezbollah and recommended UNIFIL relocate 5 kilometers (3 miles) north "to avoid danger as fighting intensifies".

Danon said "Israel has no desire to be in Lebanon, but it will do what is necessary" to drive Hezbollah from its northern border so 70,000 displaced residents can return to their homes in northern Israel.

The UN has more than 10,400 peacekeepers in Lebanon.

Israeli strikes have killed at least 2,169 people in Lebanon over the last year, the Lebanese government said in its daily update. The majority have been killed since Sept 27, when Israel expanded its military campaign.

Hezbollah cross-border fire at Israel has killed 53 people over the same period, more than half of them civilians, according to Israeli authorities.

Also, a senior Hezbollah official eluded an Israeli assassination attempt on Thursday in Beirut, three security sources said.

Wafiq Safa, who heads Hezbollah's liaison and coordination unit responsible for working with Lebanese security agencies, was targeted by Israel on Thursday night but survived, the security sources said.

Earlier on Thursday, a Lebanese security source told Reuters that Israeli airstrikes on central Beirut targeted at least one senior official in Iran-backed Hezbollah.

The Israeli strikes hit a densely packed residential neighborhood of apartment buildings and shops in the heart of Beirut. Israel had not previously struck the area, which is removed from Beirut's southern suburbs where Israel has repeatedly bombed Hezbollah's headquarters.

The number of casualties rose quickly, and as midnight approached the Lebanese Health Ministry reported 22 people killed and 117 wounded. Among the dead was a family of eight, including three children, who had evacuated from the south, according to a security source.

Meanwhile, in Gaza, at least 28 people including women and children, were killed Thursday in an Israeli airstrike on a school sheltering displaced people in central Gaza, while three hospitals in the north were told to evacuate, putting patients' lives at risk, medics said.

The strike in Gaza occurred in the city of Deir Al-Balah, where a million people have taken shelter after fleeing fighting elsewhere after more than a year of war.

The Israeli military said on Thursday it had carried out a "precise strike on terrorists" who had a command-and-control center embedded in a school.

The Palestinian militant group denied the accusations. Medics said 54 other people were injured at the school.

Agencies contributed to this story.