Iran reclosed the Strait of Hormuz, which it had temporarily opened under the Israel-Lebanon ceasefire agreement, after just one day. With the US-Iran two-week truce set to expire on the 21st (local time), the swiftly shifting situation is deepening uncertainty around US-Iran talks to end the war.

The Islamic Revolutionary Guard Corps (IRGC) said on the 18th that the Strait of Hormuz was closed again from that afternoon and would not be opened unless the United States lifts its maritime blockade on Iran. In a statement posted on its own propaganda outlet, the IRGC Navy warned, “Any attempt to approach the Strait of Hormuz will be regarded as cooperation with the enemy, and the vessel will be a target.”

This overturned, after only one day, the previous day declaration by the Iran Ministry of Foreign Affairs that fully permitted merchant shipping through the Strait of Hormuz. The IRGC claimed that a reaffirmation by the United States that it would continue the maritime blockade against Iran violates the two-week truce agreement. Some analyses also see the abrupt return to a hard line by the Iranian military as exposing tensions between hardliners in the armed forces and the political leadership.

The Iranian military also moved to the immediate use of force. The United Kingdom Maritime Trade Operations (UKMTO) said that, after the re-closure announcement, it had received reports that tankers and container ships transiting the Strait of Hormuz had been struck. Some vessels in the Hormuz area were also said to have received Iranian Navy radio messages stating, ‘The Strait of Hormuz is closed again. Vessels cannot pass’.

With tensions around the Strait of Hormuz rising again, prospects for a second round of US-Iran talks have also grown uncertain. After the two sides accepted a two-week truce proposed by Pakistan, US-Iran back-channel talks had continued with the 21st as the deadline, and expectations for a breakthrough had been building following the ‘opening of Hormuz’ announcement. The US online outlet Axios reported that President Donald Trump convened a White House Situation Room meeting that day to discuss the renewed closure of the Strait of Hormuz and related developments.

President Trump remains publicly optimistic about a deal. While criticizing Iran with remarks such as “They wanted to close the strait again, but they cannot bully us” and “They are being a bit crafty, as they have been for 47 years,” he also said that end-of-war talks with Iran are “going smoothly.” He added, “We will receive some information during the day,” hinting at the possibility of meaningful progress in the talks with Iran. A second round of US-Iran talks to end the war is being mentioned as possibly taking place on the 20th in Islamabad, Pakistan, but the schedule has not been officially confirmed.

The Supreme National Security Council of Iran said in a statement issued in the name of its secretary general that the United States had presented a new proposal and that it was under review. Asim Munir, Chief of Army Staff of Pakistan who is mediating US-Iran talks, recently visited Iran and is said to have delivered to Iran plans for a second round of end-of-war talks. However, Mohammad Bagher Ghalibaf, the speaker of parliament who heads the Iranian negotiating delegation, said in a speech broadcast on state TV on the 19th, “There has been some progress in the negotiations, but many differences and a few fundamental issues remain,” adding, “We are still far from a final agreement.”