The tunnel was said to have been more than 25 metres deep and contained "hundreds of weapons," Israeli Prime Minister Benjamin Netanyahu and Defence Minister Israel Katz said in a joint statement on Sunday evening.
Meanwhile, state-run Lebanese media reported several attacks on Sunday.
The reports come despite Friday's framework agreement between Israel, the United States and Lebanon's beleaguered government aimed at achieving peace in Lebanon. However, Hezbollah is not part of the ceasefire and has condemned the agreement.
In a statement, the movement points to Sunday's attacks as "a clear violation of the ceasefire" and says that it "reserves the right to defend its homeland and people."
