Trump Threatens Harder Strike on Iran as Ceasefire Follow-Up Talks Hit Snags on Day One

The U.S. and Iran began follow-up talks on ending the Middle East war, but the negotiations ran into sharp friction from the first day. President Donald Trump warned of further attacks on Iran, prompting reports that the Iranian delegation had walked out of the venue. The Lebanon front and Iran’s nuclear program also emerged as early flashpoints.

U.S. and Iranian negotiators met on June 21 at the Bürgenstock resort near Lucerne, Switzerland. The talks are meant to determine how to implement a recently signed ceasefire memorandum of understanding, or MOU. Vice President JD Vance led the U.S. side, while Iranian Parliament Speaker Mohammad Bagher Ghalibaf headed Tehran’s delegation.

The opening tone appeared relatively positive. Vance called the meeting “historic” and said it was a moment that would determine whether the Middle East could permanently reshape regional relations or revert to old patterns. He added that substantial progress had already been made in recent hours and that he expected more within the next few hours.

Trump’s remarks jolted the talks. In a social media post, he said Iran must immediately stop provocations by its proxies in Lebanon. Otherwise, the U.S. would hit Iran “much harder” than it did last week. The message was directed at Hezbollah, the Iran-backed armed group in Lebanon.

Iran reacted immediately. State-run IRNA reported that the Iranian delegation left the building where the talks were being held after meeting with mediators from Qatar. The negotiations did not appear to have collapsed altogether, however. AFP, citing a diplomat familiar with the matter, said the Iranian delegation was still involved in the talks and had not told mediators it intended to leave the negotiating table. Reuters, also citing an Iranian source, reported that the talks had been paused temporarily rather than ended.

Tehran also refused to back down. Ghalibaf said the U.S. should choose its words carefully and that Iran’s military was prepared to respond in other ways. Foreign Ministry spokesman Esmail Baghaei said it would be impossible to move to negotiations on a final agreement unless the war in Lebanon ended.

The MOU included a halt to fighting between Israel and Hezbollah, but clashes in Lebanon have continued since then, adding pressure to the talks. Iran has objected to Israeli airstrikes in Lebanon and raised the option of re-closing the Strait of Hormuz. Because the MOU centered on reopening passage through the waterway, the Lebanon issue is now directly tied to the strait as well.

Israel has also maintained a hard line. Prime Minister Benjamin Netanyahu said Israel would not retreat from blocking Iran from obtaining nuclear weapons or from keeping military pressure on Hezbollah. He said Israel would remain in the security zone in southern Lebanon for as long as necessary and would never allow Iran to possess nuclear weapons.

The nuclear issue remains a central obstacle in the follow-up talks. The U.S. did not include concrete steps in the MOU to prevent Iran from obtaining nuclear arms, leaving that discussion to later negotiations. The fate of highly enriched uranium, the duration of any enrichment halt, the dismantling of nuclear facilities and international verification are all issues the two sides are unlikely to resolve easily.

Iranian President Masoud Pezeshkian said on June 21 that Iran has no intention of developing nuclear weapons. At the same time, he said Tehran would not give up its right to enrich uranium. Trump responded in a phone interview with a Fox News reporter by saying Pezeshkian should “watch his mouth.”

Terms for passage through the Strait of Hormuz are another source of conflict. Iran plans to keep the strait open free of charge only during the 60-day follow-up negotiating period. After that, it intends to effectively impose transit fees under the pretext of providing services. The U.S. says the waterway must remain open without charge.

Trump has also repeated his claim that if the negotiations fail, the U.S. could take control of the Strait of Hormuz and take 20% of the oil passing through it. Senator Lindsey Graham told CBS that he believes the talks with Iran will fail and that Trump would then seize control of the strait and collect operating fees.

Iran said the first round of talks focused more on implementing the MOU and the situation in Lebanon than on its nuclear program. The U.S. wants to speed up follow-up talks aimed at ending the war, but the Lebanon front, the Strait of Hormuz and Iran’s nuclear program have become entangled from the outset, throwing the negotiations into turbulence.

Hong Min-seong, Hankyung.com reporter mshong@hankyung.com