Direct negotiations between the United States and Iran are scheduled to open in Switzerland even as Iranian forces claim they have once again sealed the Strait of Hormuz in reaction to Israeli strikes across southern Lebanon.

Tehran also pointed to an alleged violation of its prior understanding with Washington to halt hostilities. US military officials, however, stated that normal traffic continues through the vital passage.

Vice President JD Vance reached Switzerland early Sunday, with the latest round of discussions expected to commence later that day.

An Iranian team led by parliamentary speaker Mohammad Bagher Ghalibaf and Foreign Minister Abbas Araghchi arrived on Saturday evening.

Representatives from both nations will be joined by Pakistan's Prime Minister Shehbaz Sharif and armed forces chief Field Marshal Asim Munir.

Pakistan's Foreign Ministry issued a statement confirming its ongoing support for carrying out the agreements reached between Iran and the United States.

Vance expressed hope for advances on nuclear matters and the Lebanon ceasefire during the meetings.

Before departing, he told reporters that clashes involving Israel and Hezbollah had eased somewhat and that progress was visible on the ground.

He stressed the need for continued management to protect both Israel and Lebanon while working toward broader regional stability.

Iranian foreign ministry spokesman Esmail Baghaei indicated that Tehran would press the other party to honor its pledges.

Earlier in the week the US and Iranian presidents endorsed a preliminary accord to halt fighting, including in Lebanon, right away and to pursue a final settlement within the following 60 days.

Persistent exchanges between Israel and the Iran backed Hezbollah group in Beirut's southern suburbs have added complications.

At least 47 people died in Lebanon on Saturday from Israeli air strikes, according to the health ministry there.

The Israel Defense Forces reported hitting 80 Hezbollah linked sites and eliminating dozens of fighters, while also confirming four of its own soldiers were killed.

Despite the announced deal, Israel and Hezbollah kept trading fire until an immediate ceasefire took effect on Friday afternoon.

Before the accord Israel had ruled out pulling its troops from Lebanon and treated its Hezbollah conflict as distinct from the wider confrontation with Iran.

Hezbollah accused Israel of trying to undermine the larger US Iran understanding through continued attacks.

The US government has voiced disapproval of Israel's operations in Lebanon, which became involved after Hezbollah fired rockets in response to earlier US Israeli strikes that killed Iran's supreme leader.

Lebanon's health ministry reported a total of 4,057 deaths since fighting between Israel and Hezbollah resumed on 2 March.

Iran's Islamic Revolution Guard Corps accused Israel of breaching ceasefire terms and announced that the Strait of Hormuz, previously reopened following the US Iran deal, had been closed again.

The Iranian military justified the move by claiming the United States failed to enact the first clause of their 14 point memorandum, which called for immediate and lasting cessation of military actions on every front including Lebanon.

US Central Command spokesperson Tim Hawkins responded that traffic was still moving normally, that forces were watching developments, and that Iran does not control the strait.

Centcom noted that 55 merchant vessels passed through on Saturday carrying over 17 million barrels of oil destined for global markets.

Iran had previously restricted access to the strait following US and Israeli strikes on the country that began on 28 February, disrupting energy markets worldwide.

The waterway accommodates the largest crude carriers and serves major oil and liquefied natural gas exporters along with their buyers.

Estimates from the US Energy Information Administration indicate roughly 20 million barrels of oil and products transited daily in 2025, representing nearly 600 billion dollars in annual energy trade.