Both sides have accused each other of violating the deal; Hezbollah fired into Israel for the first time since the truce took effect, and Israel responded with airstrikes.

Hezbollah has claimed the first strike against Israel since a US-backed cease-fire plan came into effect less than a week ago, prompting Israeli officials to vow a strong response in the most serious threat so far to the truce with Lebanon.

The Israeli military says Hezbollah has fired into a disputed border zone, the group's first attack since a ceasefire took hold last week.