BEIRUT >> The Israeli military on Thursday warned people to evacuate a city and other communities in southern Lebanon that are north of a U.N.-declared buffer zone, signaling that it may widen a ground operation launched earlier this week against the Hezbollah group.

Israel has told people to leave Nabatieh, a provincial capital, and other communities north of the Litani River, which formed the northern edge of the border zone established by the U.N. Security Council after the two sides fought a war in 2006. Each side accuses the other of violating the resolution.

At least nine Israeli soldiers have been killed in clashes with Hezbollah in southern Lebanon, where Israel announced the start of what it says is a limited ground incursion earlier this week. Meanwhile, the region is bracing for Israeli retaliation following an Iranian ballistic missile attack.

The World Health Organization reported that 28 health workers were killed in the past day in Lebanon, and access to medical care is becoming limited as three dozen health facilities closed in the south and five hospitals were either partly or fully evacuated in Beirut.

The Lebanese health minister said Israeli strikes that hit nine hospitals and 45 health care centers violate international law and treaties.

“This is a war crime, there is no doubt about that,” Firas Abiad said. “International laws are clear in protecting these people — I mean, paramedics. Who gave Israel the right to be the judge and the executioner at the same time?”

The Lebanese Red Cross said an Israeli strike wounded four of its paramedics and killed a Lebanese army soldier as they were evacuating wounded people from the south. It said the convoy near the village of Taybeh, which was accompanied by Lebanese troops, was targeted Thursday despite coordinating its movements with U.N. peacekeepers. There was no immediate comment from the Israeli military.

Another Lebanese soldier was killed by Israeli fire at an army post in the southern town of Bint Jbeil, according to the Lebanese military, which said it returned fire. A Lebanese security official, who spoke on condition of anonymity according to regulations, said the army post was hit by artillery fire.

An Israeli airstrike on an apartment in central Beirut late Wednesday killed nine people, including seven Hezbollah-affiliated civilian first responders. Israel has been pounding areas of the country where the group has a strong presence since late September, but has rarely struck in the heart of the capital.

There was no warning before the strike late Wednesday, which hit an apartment not far from the United Nations headquarters, the prime minister’s office and parliament.

Residents reported a sulfur-like smell following the strike in Beirut, and Lebanon’s state-run National News Agency — without providing evidence — accused Israel of using phosphorous bombs, which can cause severe burns and could violate international law. Human rights groups have in the past accused Israel of using white phosphorus incendiary shells on towns and villages in southern Lebanon.

The Israeli army said it has shells containing white phosphorous that do not violate international law, but it did not say if they were used in the attack. Army officials said the primary shells they use to create a smokescreen do not contain the substance.

The Palestinian Health Ministry says 14 people were killed Thursday in an Israeli strike in the Tulkarem refugee camp in the West Bank.

The Israeli military said it conducted a strike in Tulkarem, without elaborating. Tulkarem is a fighter stronghold in the northern West Bank.

The military said the operation was carried out in coordination with the Shin Bet internal security service, but it gave no details on the target.

Violence has flared across the Israeli-occupied territory since the Israeli-Hamas war erupted last October. Tulkarem and other northern Palestinian cities have seen some of the worst violence.