How the U.S.–Iran Ceasefire Collapsed: Strait of Hormuz, the Fifth Round of Strikes, and What Comes Next

The 60-day ceasefire between the United States and Iran, codified in the June 17, 2025 Memorandum of Understanding (MOU), collapsed after roughly three weeks. The immediate trigger was a dispute over control of the Strait of Hormuz, the narrow waterway through which about one-fifth of the world's oil passes . The MOU had called for a "dual blockade" to be lifted, allowing commercial shipping to resume, but both sides accused each other of failing to implement the terms . Iran began striking commercial vessels transiting the strait, and the U.S. responded with multiple rounds of airstrikes . On July 8, 2025, at the NATO summit, President Trump declared the ceasefire over, saying "I don't want to deal with them anymore … as far as I'm concerned, it's over" . He approved additional strikes on Iranian military facilities near southern ports and the Strait of Hormuz .

The Fifth Round of U.S. Strikes — What Did It Target?

Reports describe a large "fifth round" of U.S. strikes on July 9–10, 2025. U.S. Central Command stated that it struck approximately 90 targets across Iran, releasing black-and-white footage of operations that showed strikes on an airport runway and missile launchers . Iranian officials reported explosions near Iran's sole nuclear power plant at Bushehr and in several other locations across the country . Earlier rounds had focused on Iranian military facilities near southern ports and the Strait of Hormuz . This fifth round represented a significant widening of the target set, moving beyond nuclear sites to include conventional military infrastructure and infrastructure near the Bushehr nuclear complex.

How Iran Responded

Iran's response was swift and multi-pronged. Iran launched missiles targeting U.S. partners Kuwait and Bahrain, though U.S. officials said the missiles either malfunctioned or were intercepted . Iran also ceased communication with U.S. mediators through Qatar and Oman, further signaling the breakdown of diplomatic channels . Iranian officials publicly accused the U.S. of striking near the Bushehr nuclear plant, and state media reported explosions across multiple provinces . The response was consistent with earlier threats: Iran's Supreme Leader had vowed in late June 2025 to attack U.S. bases if the U.S. struck Iran again, and Iranian armed forces had already demonstrated their reach with a June 23 attack on Al Udeid Air Base in Qatar .

Broader Implications

Strait of Hormuz

The dispute over control of the Strait of Hormuz was the proximate cause of the ceasefire's collapse, and its status remains the central unresolved issue. The MOU had agreed only in principle to resume navigation through the strait but did not clarify which party would manage and control passage . On July 12, the IRGC Navy declared the strait closed after claiming to have fired warning shots at a ship attempting to cross an unauthorized route . Traffic through the strait remains unpredictable, and analysts describe Hormuz transit as "likely to remain unpredictable for the foreseeable future" .

Oil Prices

Oil markets reacted immediately and violently. When the ceasefire was signed in mid-June, Brent crude fell to around $79.85 a barrel, reflecting market relief . As the truce unraveled in early July, prices spiked roughly 7% in a single day, with Brent reaching $79.07 and West Texas Intermediate surging . The spike was the largest single-day gain for both benchmarks since April . On July 9–10, prices slid about 2% to around $76.30 as economic demand worries tempered supply fears . However, the underlying vulnerability remained: Brent briefly topped $80 per barrel on July 8 before retreating . Both NPR and Politico reported that the collapse injected "fresh uncertainty" into global markets, with stock prices falling alongside the oil spike . The International Energy Agency warned that the return of fighting threatened to extend the global energy crisis and that world oil demand was on track to fall for the first time since 2020 .

Status of the June 17 MOU

The MOU is effectively defunct. Trump declared it over on July 8, and both sides resumed active hostilities . No new ceasefire framework has been proposed, and negotiations through Qatari and Omani mediators have stalled . The collapse of the 60-day framework also undermined the temporary waiver of sanctions on Iranian oil that had been in place, with the U.S. revoking the license on July 7 .

The Bigger Picture

The rapid unraveling of the ceasefire underscores a critical flaw in the June 17 MOU: it established a cessation of hostilities and a framework for reopening the Strait of Hormuz, but it left the most contentious issue — who controls and manages the waterway — unresolved. The resulting ambiguity gave both sides grounds to accuse the other of non-compliance, and neither showed willingness to back down . For global energy markets, the collapse means the era of uninterrupted Gulf oil flows is over, according to Reuters analysts, and traders will need to price a higher geopolitical risk premium into crude for the foreseeable future .