U.N. peacekeepers in Lebanon urged immediate de-escalation as hostilities rumbled on at the Lebanese-Israeli border on Friday, following Israel's most intense airstrikes in nearly a year of conflict with the Iran-backed Hezbollah.

Tensions between Israel and Hezbollah have intensified in recent days amid an escalation in cross-border warfare since the start of Israel’s deadly war on the Gaza Strip, which has killed nearly 41,400 people, mostly women and children, following a cross-border attack by the Palestinian group Hamas on Oct. 7 last year.

Israel launched a wave of airstrikes against Hezbollah targets in southern Lebanon, just as the militant group’s leader said two days of exploding pagers and walkie-talkies amounted to a declaration of war.