BEIRUT — The UN’s special coordinator for Lebanon has criticized Israel after air strikes on municipal buildings in the southern city of Nabatieh killed the mayor and 15 other people.

Jeanine Hennis-Plasschaert called the killing of mayor Ahmad Kahil “alarming” and said any violations of international humanitarian law were “completely unacceptable”.

At least five of those killed in Wednesday's strike were municipal staff co-ordinating aid for civilians remaining in the area, Nabatiyeh Governor Howaida Turk told the BBC.

Lebanon’s caretaker prime minister, Najib Mikati condemned the attack, saying it had "intentionally" targeted a council meeting.

The attack was the most significant against a Lebanese state building since the latest escalation in fighting, which began about two weeks ago, and has raised concerns about the safety of the country’s state infrastructure.

A spokesman for the Israeli military said its forces had launched raids targeting dozens of Hezbollah targets in the area and destroyed a tunnel used by the Iran-backed group.

"We know that Hezbollah many times takes advantage of civilian facilities," Israel's UN ambassador Danny Danon said at a meeting of the UN in New York City on Wednesday.

Turk, the governor, said that while the majority of Nabatieh residents had already left the area following heavy Israeli air strikes, the mayor and other municipal employees had stayed behind to help those who remained.

“This is just like strikes all over Lebanon,” she said.

“They [Israel] have hit civilians, Red Cross, civil defense. Now they have targeted a government building. It is unacceptable. It is a massacre.”

Previous strikes on Nabatieh over the past few days have destroyed historic buildings, including an Ottoman-era market dating to 1910.

Israel also launched at least one air strike against Beirut on Wednesday.

The strike, which hit the southern suburb of Dahieh, was the first on the Lebanese capital in five days. It came after a reported intervention by the US in which it urged restraint over the bombing of the capital.

Residents of Dahieh had begun to return to the area over the past few days, taking advantage of the apparent pause in bombing to check on their homes and retrieve clothes and other possessions.

Several told the BBC on Wednesday that the area resembled a ghost town, with rubble and debris from buildings littering the streets.

The strike on Dahieh came just hours after a US state department spokesman Matthew Miller publicly expressed concern over the “scope and nature” of Israel’s bombing of Beirut.

Miller said the State Department’s concerns had been "made clear to the government of Israel".

An Israeli military spokesman said that prior to striking Beirut, “numerous steps were taken to mitigate the risk of harming civilians, including advancing warnings to the population in the area”.

Israel has faced criticism this week over its warnings, which Amnesty International has called “inadequate” and “misleading”.

The human rights charity said the warnings did “not absolve Israel of its obligations under international humanitarian law”.

Israel has expanded its air campaign in recent days, launching an unexpected strike in the far north of the country on Monday.

The strike, which destroyed a large residential home that had been rented by a displaced family in the Christian village of Aitou, killed 23 people, according to the Lebanese health ministry.

Twelve of the dead were women and two children, the ministry said.

The UN human rights office called for an investigation into the Aitou strike, saying it raised "real concerns" with respect to international humanitarian law. — BBC