Trump warns Iran as Lebanon fighting threatens ceasefire

President Donald Trump warned Iran on June 21 to stop Hezbollah and other proxies operating in Lebanon or face stronger U.S. strikes, four days after he signed a ceasefire memorandum intended to end the Iran war.

Trump posted the warning on Truth Social at 9:30 a.m. Eastern, writing, “Iran must immediately stop their highly paid PROXIES in Lebanon from causing trouble. If they don’t, we’ll hit Iran very hard again, just like we did last week, only harder!!!” The post was signed “President DONALD J. TRUMP.” He also wrote that ships would transit the Strait of Hormuz toll-free for 60 days “unless they are imposed by and for the United States of America,” if a final deal collapsed.

The memorandum of understanding was signed on June 17 in Versailles, France, by Trump and Iranian President Masoud Pezeshkian, with Pakistan’s prime minister acting as mediator. The 14-point document calls for an immediate and permanent end to military operations on all fronts, including Lebanon, and sets a 60-day period to negotiate a comprehensive agreement on Iran’s nuclear stockpile, missile program and staged sanctions relief. Israel and Hezbollah did not sign the memorandum.

Violence flared after the memorandum took effect. On June 19, Israeli strikes in southern Lebanon killed at least 18 people, the deadliest single incident since the agreement. The Israel Defense Forces described the strikes as a response to repeated violations of the ceasefire.

Iran closed the Strait of Hormuz for the second time in a week, citing continued Israeli troop activity in Lebanon as a breach of the memorandum. The waterway carries roughly 20% of global crude oil and liquefied natural gas shipments. Brent crude traded near $78 a barrel on Saturday.

Technical-level negotiations between U.S. and Iranian delegations resumed at the Bürgenstock resort in Switzerland over the weekend. Vice President JD Vance, U.S. special envoy Steve Witkoff and Jared Kushner are representing Washington. Iranian Foreign Minister Abbas Araghchi and Parliament Speaker Mohammad-Bagher Ghalibaf lead Tehran’s team. Pakistani and Qatari officials are mediating, and organizers added an emergency session on the Lebanon fighting to the agenda.

The memorandum opened access to a $300 billion reconstruction fund for Iran and a staged path to sanctions relief, with both measures contingent on verified compliance. U.S. critics, including several Senate Republicans, contend that continued fighting in Lebanon gives Tehran room to flout the agreement and weakens U.S. leverage. Ongoing Israeli operations in Lebanon pose a test for how much influence the United States can exert over Israeli military decisions.

The memorandum sets a 60-day clock to reach a final, verified agreement on Iran’s nuclear stockpile and missile program. Negotiators and regional actors must address the recent fighting in Lebanon during that period to keep the talks on course.