Separately, Israeli airstrikes on the Gaza Strip killed eight Palestinians, including five children, on Monday morning, according to Palestinian medical officials.
Residents of different villages in southern Lebanon posted photos on social media that they said showed their towns that were being struck. The state-run National News Agency also reported airstrikes in different areas.
The Israeli military's Arab-language spokesperson said the air force was attacking targets related to Hezbollah.
The wave of airstrikes came after a tense day in which Hezbollah fired over 100 rockets into northern Israel, with some landing near the city of Haifa. Israel launched hundreds of airstrikes as well.
Hezbollah's rocket attack came after an Israeli airstrike on a Beirut suburb on Friday killed a top Hezbollah military commander and more than a dozen Hezbollah members, along with dozens of civilians including women and children.
Last week, thousands of communications devices, used mainly by Hezbollah members, exploded in different parts of Lebanon, killing 39 people and wounding nearly 3,000. Lebanon blamed the attacks on Israel, but Israel did not confirm or deny its responsibility.