Israeli strikes on south Lebanon on Friday killed four people including a paramedic and a woman, Hezbollah and affiliated rescuers said, with the Iran-backed group adding it had fired dozens of rockets in retaliation.
Hezbollah, a Hamas ally, has traded regular cross-border fire with Israel during Tel Aviv's war on the Gaza Strip.
The operations room of the Hezbollah-affiliated Islamic Health Committee told AFP that "an Israeli drone strike targeted an ambulance… One rescuer was martyred and another wounded" in the border town of Naqura.
Lebanon's official National News Agency (NNA) also said "an enemy drone targeted a Health Committee ambulance in the town of Naqura", reporting casualties.
Several militant groups in Lebanon operate health centres and emergency response operations.
The operations room later told AFP that an Israeli strike on the town of Adloun had killed a woman and wounded four other people.
The NNA said an "enemy drone launched a strike targeting a house" in Adloun, around 30 kilometres (nearly 20 miles) from the border, "completely destroying it".
The Israeli military said in a statement that "fighter jets struck a military structure" in the Naqura area "where a terrorist cell's activity was identified".
"A terrorist" in the Yarun area, elsewhere in south Lebanon, "was also struck", the statement said, adding that a drone from Lebanon was intercepted.
Hezbollah said it fired "dozens of Katyusha rockets" at northern Israel "in response to the attack" in Naqura, and also claimed other attacks on Friday, including with drones and heavy-duty missiles.
The Shia Muslim group announced in separate statements that two of its fighters had been killed, without specifying where.
A source close to Hezbollah had said one person was killed in bombardment in Ain Qana, without elaborating.
Imran Riza, the UN's humanitarian coordinator for Lebanon, said on X that he was "deeply disturbed to hear that an ambulance was targeted" in south Lebanon.
"20 health workers killed since 8 October", he added.
Nearly 450 people have been killed in Lebanon in more than seven months of cross-border fighting, mostly militants but also more than 80 civilians, according to an AFP tally.
Ten rescuers from the Islamic Health Committee are among those killed.
Israel says 14 soldiers and 11 civilians have been killed on its side of the border.
Also on Friday, Lebanon's foreign ministry said the country had submitted a complaint to the UN Security Council over a strike blamed on Israel this month on a car that also damaged a nearby minibus, wounding several schoolchildren.
A source close to Hezbollah said one of the group's fighters was killed in that strike.
The attack was "a violation of international humanitarian law", the foreign ministry said, urging the Security Council to "condemn Israel's direct, deliberate, repeated targeting of civilians".
Hezbollah chief Hassan Nasrallah meanwhile in a televised address warned that the group's fighters were capable of penetrating into northern Israel but had not done so.