The woman and girl were killed in the strike near Majdal Zoun, a village some 6 km (4 miles) from the border, according to two security sources and a medical source.
The father of the six-year-old girl killed said she had asked to visit her village, which they had fled from after the eruption of hostilities last year, in comments broadcast by al-Akhbar newspaper.
The Iran-backed Hezbollah movement has been trading fire with Israel since the Oct. 7 attack by its Palestinian ally Hamas on southern Israel in a campaign Hezbollah says aims to support Palestinians in the Gaza Strip.
The Israeli army said its warplanes had struck three Hezbollah operational command centers in southern Lebanon.
It said Israeli army artillery had also fired "to remove a threat" in the areas of Alma al-Shaab and Dhayra, both villages at the border.
The Israeli army did not respond to a request for comment about reports of the strike in Majdal Zoun.
Hezbollah signalled on Friday it would escalate attacks on Israel in response to the deaths of 10 Lebanese civilians in Israeli attacks last week.
Hezbollah announced more than half a dozen attacks on Israeli positions on Wednesday.
Israeli strikes since Oct. 8 have killed some 50 civilians in Lebanon, in addition to nearly 200 Hezbollah fighters.
Attacks from Lebanon into Israel have killed a dozen Israeli soldiers troops and five civilians.
The violence has uprooted tens of thousands of people on both sides of the border.
(Reporting by Laila Bassam in Beirut and Ari Rabinovitch and James Mackenzie in Jerusalem; Writing by Tom Perry; Editing by Peter Graff and Angus MacSwan)
