Israel warned Friday that it would keep striking Lebanon until militant group Hezbollah has been disarmed, hours after hitting south Beirut in what Lebanese leaders called a major violation of a November ceasefire.

The Israeli military struck several sites in Beirut’s southern suburbs that it said held underground facilities used by Hezbollah for drone production Thursday, on the eve of the Eid al-Adha holiday.

The airstrikes on the southern outskirts of the Lebanese capital, an area where Hezbollah holds sway, were some of the heaviest since a U.S.-brokered cease-fire came into effect in November.