Hormuz Ceasefire Collapses: Iran Rejects UN Resolution, Military Strikes Escalate, and Diplomacy Stalls as 60-Day Window Expires

The 60-day ceasefire between the United States and Iran expires on Monday, August 17, 2026, with no permanent agreement in place and little sign of progress. The standoff over the Strait of Hormuz — the world's most critical oil chokepoint — has already seen weeks of heavy military exchanges, a failed UN Security Council resolution, and a dramatic breakdown in diplomatic talks. Here is a clear, sourced timeline of the key events and what they mean for the region and global energy markets.

Iran Rejects the US-Backed UN Resolution

Iran categorically rejected the US-backed draft resolution on the Strait of Hormuz, calling it "deeply flawed and one-sided" during a Security Council stakeout in May 2026 . Tehran argued the proposal was politically motivated and would "legitimise unlawful actions" rather than resolve the conflict . Iran's UN mission stated that the "only viable solution" is "a permanent end to the war, the lifting of the maritime blockade, and the restoration of normal passage" . Foreign Minister Abbas Araghchi described the resolution as advancing a US "political agenda" while ignoring what Iran calls the root cause: US-Israeli aggression against Iran since late February .

A separate draft resolution on Hormuz, backed by Bahrain and the US, had been vetoed by Russia and China at the Security Council in April 2026 . A subsequent resolution (2817) condemning Iranian attacks on Gulf states was adopted in July .

Timeline of Military Escalations

The diplomatic breakdown was accompanied by a heavy exchange of fire between Iran, the US, and Gulf Cooperation Council (GCC) forces.

• July 11, 2026 — Iran declared the Strait of Hormuz closed to unauthorized vessels and said it would hit any ship violating its permit system. The US said it struck hundreds of Iranian targets after Iranian ship attacks, and Iran retaliated by targeting multiple Gulf states .
• July 12, 2026 — A US Navy ship came under attack in the Gulf of Oman. Iran said it would restart shipping permits once calm was restored .
• July 14, 2026 — The US restarted its naval blockade against vessels transiting to and from Iranian ports .
• July 15, 2026 — The US and Iran traded fire for the sixth consecutive day. US Central Command struck Iranian command centers, air defense sites, and missile and drone capabilities .
• Late July 2026 — The US carried out a 13th consecutive night of strikes on Iran. The Pentagon insisted the Strait was open, but traffic was at a crawl and oil prices pushed back over $100 per barrel .
• August 4, 2026 — An Iranian general warned that US warships attempting to establish an alternative shipping corridor through Hormuz "could become targets." Iran also claimed it had foiled a US ground attack plan .
• August 8, 2026 — Iran's Supreme National Security Council issued sweeping new demands, stating the Strait would not open until the US "corrects its behavior," including that the US must never threaten Iran again and must lift all sanctions. Iran also warned Saudi Arabia over a new trilateral Mecca defense pact .

The 60-Day Ceasefire: From Signing to Stalemate

• June 17, 2026 — President Trump and Iranian President Pezeshkian signed a 14-point memorandum of understanding (MoU) in Evian, France, establishing a ceasefire and a 60-day window to negotiate a permanent end to the war. The MoU called for removal of the US naval blockade and Iranian safe-passage arrangements for commercial vessels without charge for 60 days .
• May 28, 2026 (prior to the Evian signing) — US and Iranian negotiators had reached a tentative agreement to extend an earlier ceasefire by 60 days and launch nuclear talks .
• The ceasefire began fraying within weeks amid renewed clashes and mutual accusations of violations .
• Early August 2026 — Axios and other outlets reported the US, Iran, and Oman were close to an interim agreement to reopen the Strait and revive the ceasefire, with an announcement expected imminently . Iran's Foreign Minister Araghchi said Tehran was "very close to an agreement" with Oman .
• August 8, 2026 — Iran released a new list of drastic demands via the Supreme National Security Council, insisting the Strait would not reopen unless those conditions were met. Iran also accused the US of violating the MoU .
• August 12, 2026 — Mediators were still pushing for US-Iran talks, but a senior Iranian source said there had been no progress and Iran rejected reports of an extension .
• Today (August 16, 2026) — The 60-day ceasefire under the MoU expires Monday, August 17, with no confirmed extension and no permanent deal reached. Reports indicate no significant progress on a final agreement, raising the risk of a return to full hostilities .

What Happens Now?

With the ceasefire window closing, the immediate risk is a return to the intense military exchanges seen in July. The US maintains a naval blockade on Iranian ports and has hundreds of warships and aircraft in the region. Iran has signaled it will not reopen the Strait without major concessions, including a permanent end to the war, the lifting of all sanctions, and the withdrawal of US forces from the area . Global oil prices are already rising, and any renewed closure of the Strait of Hormuz would have immediate consequences for energy markets and global supply chains.

Diplomatic channels remain open through Oman, but the gap between the two sides appears as wide as ever. The coming days will determine whether the truce can be revived or whether the conflict enters a new, more dangerous phase.