Israel and the Iranian-backed Hezbollah militant group agreed Friday to halt the heavy fighting in southern Lebanon that had threatened to unravel an interim agreement between the United States and Iran to end their war, officials said. Neither Israel nor Hezbollah immediately confirmed the truce.

It came after a heavy exchange of fire killed 47 people in Lebanon and four Israeli soldiers.

Hezbollah and Israel went to war shortly after the outbreak of the wider conflict, with Hezbollah firing rockets and drones at civilian communities in northern Israel and Israel seizing large swaths of southern Lebanon.

The interim agreement to end the Iran war has already reopened the Strait of Hormuz, which Iran effectively closed, cutting the global economy off from significant supplies of oil and natural gas. The deal would also relaunch talks on Iran’s nuclear program, the core issue over which Israel and the U.S. began the war on Feb. 28.

But the accord already faces threats, chiefly from Lebanon, with the fighting there leading to a delay in the start of talks planned for Friday in Switzerland. The agreement calls for a halt to military operations in Lebanon and for its sovereignty to be respected. Neither Israel nor Hezbollah is a party to the deal.

Israeli Prime Minister Benjamin Netanyahu has vowed to keep Israeli forces in southern Lebanon until the threat is eliminated. Hezbollah has refused to halt its attacks unless Israel commits to withdrawing from Lebanon, which Iran says is also a condition of the deal.