The Lebanese health ministry says the death toll from what it says was an Israeli strike in the northern town of Aitou has risen to 21.
DNA tests are under way to determine the identity of those killed in the strike, the ministry says.
This would be the first time Israel has targeted the Christian-majority northern region in a year of hostilities.
Israel is yet to comment.
Elsewhere, a Hezbollah drone attack killed four Israeli soldiers at an Israeli army base south of Haifa on Sunday night.
It’s one of the deadliest attacks against Israel by Hezbollah in over a year of fighting.
In Lebanon, 51 people were killed by Israeli strikes across the country on Sunday, the health ministry says.
In Gaza, Hamas-run authorities say an Israeli attack on a school used as a shelter killed 22 people on Sunday, including 15 children.
The UN agency for Palestinian refugees says the building was meant to be used to administer polio vaccines.