The cancellation of talks raised questions about an initial agreement to end the war in Iran.
The crews of all three merchant vessels seized by the U.S. military over the past week are still in U.S. custody.
The area marked for evacuation includes the ancient Roman temple complex, inscribed as a UNESCO World Heritage site.
Yahya Sinwar was the chief architect of last year’s attack on Israel that sparked the multifront war.
The announcement comes just hours after Iran, on the social media platform X, warned the U.S. to keep its military forces out of Israel.
The Israeli military says it will soon launch operations on Lebanon’s southern coast, telling residents to stay off the beaches.
The region braced for further escalation as Israel vowed to retaliate for Iran's ballistic missile attack a day earlier.
Israel and the United States have warned there would be severe consequences if Iran attacks.
Israel advised people to evacuate to the north of the Awali River, about 36 miles from the border and much farther than the Litani River.
Israel has dramatically escalated strikes, saying it is targeting Hezbollah’s military capacities and senior Hezbollah commanders.