A convoy carrying US Vice President JD Vance arrives at the Burgenstock resort in Obbuergen, Switzerland, on June 21, 2026. Photo: VCG

Iranian and US negotiators have arrived in Switzerland and are expected to gather in Burgenstock resort for follow-up talks starting on Sunday on the implementation of a recently signed memorandum of understanding (MOU) aimed at ending nearly four months of conflict, as tensions persisted over the Strait of Hormuz and Israeli military operations in Lebanon. Iran announced that it had closed the key waterway after accusing Washington of failing to uphold the memorandum by restraining Israel and preventing further attacks in Lebanon, while the US military disputed Tehran's claim and said commercial shipping continued through the strait.

A Chinese expert said that the progress on the MOU suggested that both the US and Iran remained willing to negotiate, end the conflict and reach an agreement, while the mixed signals released by different parties, including continued Israeli military activity in Lebanon, reflected ongoing bargaining and pressure ahead of the talks.

US Vice President JD Vance arrived in Switzerland on Sunday, ahead of peace talks with Iranian officials that are expected to begin later today, the New York Times reported. Before departing from the US, Vance told reporters that he would only attend negotiations for a day or two, and that he hoped progress would be made on Iran's nuclear program and the ceasefire in Lebanon.

According to Al Jazeera, Esmaeil Baghaei, spokesperson for Iran's Foreign Ministry, said the Iranian delegation "will be pressing for implementation" of the US' commitments outlined in the MOU and "seeking clarity on how exactly the other side intends to carry out those commitments."

The US delegation reportedly includes Vice President JD Vance, envoys Steve Witkoff and Jared Kushner, while Iran sent a senior delegation including Parliament Speaker Mohammad Bagher Qalibaf and Foreign Minister Abbas Araghchi. 

Pakistan's Foreign Ministry said on Saturday that technical-level follow-up talks between the US and Iran will be held under the framework of the "Islamabad Memorandum of Understanding," Anadolu Agency reported on Sunday. 

According to Pakistan's government, Pakistani officials, including Prime ⁠Minister Shehbaz Sharif and army chief ⁠Field Marshal ⁠Asim Munir, as well as Qatari mediators, will join the US-Iran talks on Sunday, Al Jazeera reported. 

According to Axios, Vance reportedly said on Saturday before leaving Washington that he hopes they are going to make progress on the nuclear issue and Lebanon ceasefire issue. 

The 14-point MOU setting out a framework for talks during a 60-day negotiation period was signed by the US and Iran on Wednesday. The first clause of the MOU states that the US and Iran have agreed to the "immediate and permanent termination of military operations on all fronts, including in Lebanon." Additionally, the memorandum adds that both sides will commit to ensuring the "territorial integrity and sovereignty of Lebanon," according to Al Jazeera,

The Lebanon provision quickly emerged as an early test of whether broader commitments in the MOU could be implemented beyond the direct US-Iran confrontation. According to Reuters, two Lebanese security sources said Israel carried out a dozen airstrikes in the first hour after the ceasefire came into effect, but none were recorded after 5 pm on Friday local time. 

An Israeli military official confirmed that there had been no strikes since 5 pm, but denied that Israel had carried out a dozen strikes after 4 pm, while a Reuters journalist in northern Israel saw airstrikes ongoing inside Lebanon at around 4:50 pm, Reuters reported. 

Although Israel agreed to a renewed ceasefire with Hezbollah on Friday, its attacks in Lebanon continued into Saturday, killing at least 32 people, according to Lebanon's civil defence and state media reports, Al Jazeera reported. 

Following the renewed Israeli strikes in Lebanon, the Iranian armed forces announced on Saturday that they would close the Strait of Hormuz — just three days after it reopened — alleging that America's failure to rein in Israeli attacks on Lebanon violates the new ceasefire deal. 

The US Central Command said in an X post on Saturday that commercial vessels were continuing to transit the open Strait of Hormuz. There were reportedly 55 merchant ships transiting the Strait, moving large amounts of cargo and more than 17 million barrels of oil to global markets.

Zhu Yongbiao, a Middle East affairs expert with Lanzhou University, told the Global Times on Sunday that Iran's decision to continue the diplomatic process despite announcing the closure of the Strait of Hormuz appeared to reflect a pragmatic calculation, with Tehran seeking to press Washington to restrain Israel as much as possible rather than expecting it to exercise complete control.

Zhu said continued Israeli strikes could be aimed at preserving leverage, expanding its security buffer and drawing the US back into possible deeper involvement, while securing room to conduct periodic military operations even if Washington seeks to step back from the conflict.

Meanwhile, US President Donald Trump said in a post on Truth Social that "There will be NO TOLLS in the Hormuz Strait for 60 days during the Cease Fire Period, and there will be NO TOLLS after the 60 day period has expired, unless they are imposed by and for the United States of America."

One substantial obstacle to reaching a lasting agreement was that the memorandum remained a broad political framework, while nearly every substantive provision, including the sequencing of reciprocal steps, sanctions relief, the handling of enriched uranium, verification arrangements and the scale of US military assets in the region, could trigger major disputes once negotiations moved into technical details.

Commenting on the MOU, Chinese Foreign Ministry spokesperson Lin Jian said at a regular press conference on Thursday that China welcomes it and hopes that all relevant parties including the US and Iran will uphold the spirit of contract and implement it in good faith.