Millions of Israelis took shelter from projectiles fired back across the border.
So far the main focus of Israel's military operations in Lebanon has been in the south, the Bekaa Valley in the east and the suburbs of Beirut.
The strike in the Christian-majority town of Aitou hit a house that had been rented to displaced families, the town's mayor Joseph Trad told Reuters.
Israel has ordered residents of 25 villages in southern Lebanon to evacuate to the north. (AP PHOTO)
In addition to the deaths, eight people were injured, the Lebanese health ministry said.
Rescue workers at the site of the strike searched through piles of rubble on Monday, where burned vehicles and trees could be seen strewn across the ground.
Israel ordered residents of 25 villages in southern Lebanon to evacuate to areas north of the Awali River, which flows some 60km north of the Israeli frontier.
Prime Minister Benjamin Netanyahu, visiting a military base in central Israel where four soldiers were killed on Sunday by a Hezbollah drone strike, said Israel would continue to attack the Iran-backed movement "without mercy, everywhere in Lebanon – including Beirut".
The conflict between Israel and Hezbollah resumed in October 2023 when the militant group began firing rockets at Israel in support of Palestinian militants Hamas at the start of the Gaza war. It has escalated sharply in recent weeks.
Israeli strikes have killed at least 2309 people in Lebanon over the last year, the Lebanese government said in its daily update. The majority have been killed since late September when Israel expanded its military campaign.
As Israel has pushed its forces through south Lebanon in an attempt to wipe out Hezbollah and its military infrastructure, tensions have increased between Israel and the UN peacekeeping force UNIFIL.
A peacekeeping force's base in southern Lebanon is the site of a dispute between Israel and the UN. (EPA PHOTO)
The UN said Israeli tanks had burst into its base on Sunday.
Netanyahu on Monday rejected accusations that Israeli troops had deliberately harmed UNIFIL peacekeepers as "completely false" and repeated a call for them to withdraw from combat zones close to the border with Israel.
He said Hezbollah uses UNIFIL positions as cover for attacks that have killed Israelis, including on Sunday, when a drone attack on a military base killed four soldiers.
"Israel has every right to defend itself against Hezbollah and will continue to do so," Netanyahu said in a statement.
A UNIFIL spokesman on Monday said in a video posted on social media platform X the peacekeeping mission would stay.
"We are staying ... we are in south of Lebanon under a Security Council mandate. So it's important to keep an international presence and to keep the UN flag in the area," Andrea Tenenti said.
UNIFIL's mandate provides for its freedom of movement in its area of operations, and any restriction on this is a violation of resolution 1701.— UNIFIL (@UNIFIL_) We have requested an explanation from the IDF from these shocking violations.October 13, 2024
The Israeli military took foreign journalists into southern Lebanon on Sunday and showed them a Hezbollah tunnel shaft that was less than 200m from a UNIFIL position, as well as weapon stashes that the troops found.
"We are actually standing in a military base of Hezbollah very close to the UN," Brigadier General Yiftach Norkin said, pointing to the shaft's trapdoor in an area covered by undergrowth and overlooked by a UN observation post.
Meanwhile Israeli forces tightened their squeeze around Jabalia in northern Gaza on Monday, killing at least 10 people queuing for food, according to Palestinian medics.
Jabalia has been the focus of an Israeli offensive for around 10 days and the military has now encircled the camp and sent tanks into nearby Beit Lahiya and Beit Hanoun towns, with the declared aim of stamping out Hamas fighters who are trying to regroup there.
The United Nations human rights office said the Israeli military appeared to be "cutting off North Gaza completely from the rest of the Gaza Strip".