Fresh fighting in Lebanon has cast a shadow over the recently signed US-Iran peace accord, prompting Iran to announce the closure of the Strait of Hormuz and raising fears of a renewed regional crisis. Tehran accused Washington of failing to enforce key provisions of the agreement after Israeli strikes continued in southern Lebanon less than a day after a ceasefire took effect.
The development threatens to undermine a fragile diplomatic breakthrough that had raised hopes of ending months of conflict across the Middle East and restoring stability to global energy markets.
Iran's Khatam al-Anbiya Central Headquarters said the Strait of Hormuz was being closed to maritime traffic because of what it described as a "clear breach" of US commitments under the 14-point agreement signed earlier this week.
The first clause of the accord called for an "immediate and permanent termination of military operations on all fronts, including Lebanon".
Tehran argued that continued Israeli military operations in southern Lebanon violated that commitment. Iranian officials also pointed to civilian casualties, the displacement of residents and Israel's continued military presence in parts of southern Lebanon as evidence that the agreement was not being honoured.
The naval wing of Iran's Revolutionary Guards warned that ships attempting to pass through the waterway could face security risks.
The US military rejected suggestions that shipping through the Strait of Hormuz had been disrupted.
US Central Command said freedom of navigation remained intact and reported that 55 commercial vessels had transited the strategic waterway on Saturday. While this was the highest daily figure since the route was effectively closed during the war, it remained well below the pre-conflict average of about 130 ships a day.
The US also said naval assets would remain in the region to safeguard commercial shipping.
The Strait of Hormuz is one of the world's most important energy chokepoints, carrying a substantial share of global oil and liquefied natural gas exports. Any prolonged disruption could trigger fresh volatility in international energy markets.
The latest tensions stem from renewed clashes between Israel and Hezbollah less than 24 hours after a ceasefire was announced on Friday.
Lebanese officials said at least 23 people were killed in Israeli strikes across the Nabatieh and Saida regions of southern Lebanon.
The Israeli military said it had targeted dozens of Hezbollah positions after more than 50 projectiles were fired at Israeli forces operating in the area.
Hezbollah denied violating the ceasefire and accused Israel of attempting to advance deeper into Lebanese territory. The group said it remained committed to the truce but would resist any effort by Israeli forces to expand their presence in southern Lebanon.
Both sides have traded accusations of repeated ceasefire violations, casting doubt on the durability of the agreement.
Even as hostilities persisted, diplomatic efforts to salvage the broader peace process continued.
Pakistan, which has played a mediating role between Washington and Tehran, announced that technical-level talks involving US and Iranian officials would resume in Switzerland on Sunday. Representatives from Pakistan and Qatar are also expected to participate.
Iran's negotiating team has already departed for Switzerland, while US envoys Steve Witkoff and Jared Kushner are reportedly preparing to resume discussions.
The talks had been postponed on Friday after Israeli strikes in Lebanon prompted Iran to suspend its participation.
The violence in Lebanon now poses the most serious challenge yet to the US-Iran agreement.
The accord was intended to halt hostilities across the region and pave the way for broader negotiations. However, continuing clashes between Israel and Hezbollah, coupled with Iran's decision to reimpose restrictions on the Strait of Hormuz, have raised questions about whether the deal can survive its first major crisis.
The focus is now on President Donald Trump and whether Washington can contain the Lebanon conflict before it derails the wider peace process and reignites instability across the Middle East.