Iran has announced the closure of the Strait of Hormuz, citing renewed Israeli military operations in Lebanon which it says violate the ceasefire agreement reached with the United States to end the broader Middle East conflict.

The announcement came on Saturday as Israeli forces exchanged fire with Hezbollah fighters and carried out fresh airstrikes in southern Lebanon, despite a renewed ceasefire announced on Friday by the United States and Qatar.

Iran’s military said the continued Israeli attacks amounted to a breach of the agreement and declared that the strategic Strait of Hormuz would once again be closed to vessel traffic.

The waterway is one of the world’s most important oil and gas shipping routes, and its closure is expected to heighten concerns over global energy supplies and oil prices.

Iran had earlier agreed to reopen the strait under a preliminary peace deal brokered with the United States, but follow-up negotiations scheduled for Friday in Switzerland were postponed after the latest escalation in Lebanon.

Israel said its forces resumed operations after Hezbollah allegedly launched more than 50 projectiles at Israeli troops in southern Lebanon overnight.

Hezbollah, however, accused Israel of violating the ceasefire through what it described as an attempted military incursion and said its fighters responded to the attack.

Lebanese authorities reported multiple Israeli airstrikes across southern Lebanon, with at least 23 people killed in separate attacks, while residents in affected communities said many were preparing to flee again.

The renewed fighting has cast uncertainty over diplomatic efforts to secure a lasting peace, with planned US-Iran negotiations on Tehran’s nuclear programme and other outstanding issues now delayed indefinitely.

Meanwhile, mediators, including Switzerland, Qatar and Pakistan, are continuing efforts to revive talks aimed at preventing a further escalation of the regional conflict.