Iran said it was once again closing the vital Strait of Hormuz shipping lane over Israel’s attacks in Lebanon, calling them a violation of its deal with the United States to end the Middle East war.

Israeli troops battled Hezbollah fighters while its warplanes conducted deadly strikes in Lebanon’s south on Saturday, hours after the United States announced a renewed ceasefire in the fighting there.

In response, the US military said it remained “present and vigilant” in the Strait of Hormuz.

“US forces remain present and vigilant to ensure all aspects of the agreement with Iran are adhered to, obeyed, and in full force and effect,” US Central Command said in a statement.

The ongoing hostilities had already strained the deal signed by US President Donald Trump and his Iranian counterpart Masoud Pezeshkian this week to halt the wider regional war on all fronts, including Lebanon – a key demand of Tehran’s.

Citing a US “breach of contract” and “the Zionist regime’s continuous and relentless violation of the ceasefire in southern Lebanon”, Iran’s central military command announced “that the Strait of Hormuz will be closed to vessel traffic”.

The strait, an important conduit for oil and gas shipments, was blockaded by Iran for much of the war, sending shockwaves through global energy markets.

NABATIEH, LEBANON - JUNE 20: Smoke rises from the town of Shweikin and the Ali al-Tahir hill area in the Nabatieh Governorate of southern Lebanon following Israeli airstrikes on June 20, 2026. The attacks were carried out despite the U.S.-Iran agreement. (Photo by Ramiz Dallah/Anadolu via Getty Imag
Smoke rises from the town of Shweikin and the Ali al-Tahir hill area in the Nabatieh Governorate of southern Lebanon following Israeli airstrikes

Iran had agreed to reopen it under the preliminary agreement with the US, and shipping traffic was starting to pick back up in recent days.

It comes as US Vice President JD Vance travelled to Switzerland today for talks with Iran on implementing a deal to end the Middle East war, saying negotiators would discuss the Islamic republic’s nuclear program and the Lebanon ceasefire.

“I think we’re going to hopefully make progress on the nuclear issue, make progress on the Lebanon ceasefire issue. Those are the two big things that I think we’re to be focused on,” Mr Vance told reporters before departing from Joint Base Andrews, saying he could only join the talks “for a day or two”.

Negotiations had been planned in Switzerland on Friday, but were postponed at the last minute as Israel carried out a wave of deadly strikes in Lebanon after four of its soldiers were killed in combat.

US negotiators Jared Kushner and Steve Witkoff are already in Switzerland handling technical elements of the talks, Mr Vance said earlier.

Yesterday afternoon, a US official announced a new ceasefire between Israel and Hezbollah brokered by US and Qatari mediators, with Israel’s ambassador to Washington saying it would respect the truce if Hezbollah did.

But earlier an Israeli military official said it was conducting fresh attacks against the Iran-backed movement, which it accused of having “launched more than 50 projectiles at Israeli forces in southern Lebanon” overnight.

Hezbollah said Israel had carried out “under the cover of the ceasefire… an infiltration attempt towards the Ali Taher hills”, a strategic feature overlooking the city of Nabatieh, adding its fighters “confronted them with appropriate weapons”.

Continued clashes threaten Iran peace deal

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Lebanese state media reported Israeli air raids on around 20 locations, with the country’s civil defence agency saying 16 people were killed in the Nabatieh area, where an AFP photographer saw smoke rising over the city after strikes.

Lebanon’s health ministry reported seven more people killed and 13 wounded in a strike on a village near the city of Sidon.

Another journalist on the Israeli side of the border saw smoke billowing behind the historic Beaufort Castle, a strategic position not far from Nabatieh that Israel captured last month.

‘Right to confront’

Hezbollah lawmaker Hassan Fadlallah said that his group “has the full right to confront this enemy when it attacks us”.

An Israeli military official cited by public broadcaster Kan similarly described his country’s approach to the truce as being “on the basis of fire being answered with fire”.

Israel’s US ambassador, Yechiel Leiter, maintained it was Hezbollah that broke the truce, adding: “Israel is honouring the ceasefire while defending itself against terrorist attacks, as any self-respecting country would.”

Fadi Zayat, who had fled the southern Lebanon town of Tayr Debba, said that “fear dominates over everyone”.

“We returned to the village a few days ago, but our bags are ready to flee again,” the 53-year-old said.

“We’re waiting for a serious decision to end the war… in order to return to our lives.”

Hezbollah pulled Lebanon into the wider Middle East conflict in early March when it fired rockets at Israel in retaliation for the killing of Iran’s supreme leader in US-Israeli strikes.

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A previous ceasefire meant to take effect in Lebanon in April was never honoured.

In a call with US Secretary of State Marco Rubio yesterday, Lebanese President Joseph Aoun stressed “the need for Israeli attacks on Lebanese territory to cease”, his office said.

Mr Rubio, according to the State Department, insisted on the importance of Lebanon carrying through on its efforts to disarm Hezbollah and “re-establish control over all Lebanese territory”.

Switzerland talks

Israel and Lebanon, which have no official diplomatic ties, have held multiple rounds of US-mediated direct talks in Washington, with another scheduled next week, according to Mr Rubio.

Meanwhile, talks that were scheduled to take place between the US and Iran in Switzerland to work towards a lasting settlement in the Middle East war were postponed yesterday, with no new date announced.

US Vice President JD Vance had been expected to represent the American side, but put off his trip.

Instead, US envoy Steve Witkoff headed to Switzerland to get the talks back on track, American media outlets reported, with fellow Trump emissary Jared Kushner also expected there.

In parallel, mediator Pakistan’s interior minister Mohsin Naqvi arrived in Iran earlier for meetings with officials, Iranian media reported.

The talks in Switzerland were meant to kick off a two-month period of negotiations to discuss outstanding issues not covered by the initial deal, notably Iran’s nuclear programme.

Switzerland’s foreign ministry said that envoys “from various countries currently present are continuing their efforts to maintain the dialogue”, declining to offer further details.

Swiss public broadcaster RTS said technical delegations from the United States and Iran, plus Pakistan and fellow mediator Qatar, were present for the discussions.