The US–Iran war explained
The war that began on 28 February 2026 has reshaped the Gulf, closed the world's most important oil chokepoint and survived two attempts at a ceasefire. This is how it unfolded — with every figure dated and sourced.
Key takeaways
- US and Israeli strikes began on 28 February 2026, killing Supreme Leader Ali Khamenei.
- Iran struck US bases in five Gulf-area states and Israel, and closed the Strait of Hormuz — about a fifth of world oil.
- Brent crude rose from about $70 to above $126 (late April futures).
- An April ceasefire and a June 60-day deal collapsed on 8 July 2026.
- As of mid-October the blockade continues, ships are still being hit and a settlement remains uncertain.
The road to war
On 12 June 2025 the International Atomic Energy Agency's board found Iran in breach of its non-proliferation obligations, the first such finding in twenty years. Israel struck Iran the next day, and on 21 June 2025 the United States bombed the nuclear sites at Fordow, Natanz and Isfahan; a ceasefire followed on 23 June. The IAEA judged the strikes delayed the programme by only months.
From late December 2025, protests spread after the rial collapsed and were met with a violent crackdown. In early 2026 the United States built up its largest military presence in the region since 2003 while nuclear talks continued. They failed when Tehran would not accept US demands to end all enrichment (CFR).
28 February 2026: the strikes
The US and Israel began strikes on Iran on 28 February 2026. They killed Supreme Leader Ali Khamenei; the Assembly of Experts named his son Mojtaba Khamenei as successor. Iran retaliated against US military facilities in Bahrain, Jordan, Kuwait, Qatar and the UAE, against Israel, and against Gulf energy and civilian infrastructure (CFR).
The Strait of Hormuz
The narrow channel between Iran and Oman is the world's most important oil chokepoint: about 21 million barrels a day — roughly one-fifth of world oil supply — crossed it in the first half of 2025 (US Energy Information Administration, via CFR). Iran laid mines and repeatedly closed the strait; ship traffic fell by about 70%. One analysis described the disruption as among the largest in the history of the oil market. The United States answered with a naval blockade of Iranian ports.
The oil shock
Brent crude traded around $70 a barrel before the war. June Brent futures spiked above $126 in late April 2026 (AP). By 16 October 2026 Brent was around $106 (GlobalSecurity.org, an estimate). We show only these sourced points rather than an invented daily price line.
Ceasefire — and collapse
- 7 April 2026: a two-week ceasefire begins; sporadic strikes continue.
- June 2026: a Pakistan-mediated memorandum promises to reopen the strait, a 60-day halt to hostilities and the lifting of the US naval blockade.
- 8 July 2026: the truce collapses after renewed attacks on shipping; Iran closes the strait again and the US revives its blockade (CFR).
The human cost
Complete casualty figures do not exist. The counts below are the latest we could source, each with its date:
| Measure | Count | Source and date |
|---|---|---|
| US service members killed | 13 | NPR via CFR, as of 14 Mar 2026 |
| Iranian civilian deaths | 1,701 | HRANA via Time, as of 21 Apr 2026 |
| People displaced | up to 3.2 million | UNHCR |
Where it stands (16 October 2026)
The Strait of Hormuz has been closed again since July and the US naval blockade is being enforced. Ships continue to be hit in and near the strait; in mid-October, two container ships sank after missile strikes. CFR rates the conflict as worsening, and a settlement remains uncertain.
Frequently asked questions
When did the US–Iran war start?
On 28 February 2026, when the US and Israel began strikes on Iran after Tehran refused to end uranium enrichment. The strikes killed Supreme Leader Ali Khamenei. As of 16 October 2026 the war was in its 231st day.
Why does the Strait of Hormuz matter?
About 21 million barrels of oil a day — roughly a fifth of world supply — passed through it in early 2025. After Iran mined and closed it, ship traffic fell by about 70%, one of the largest oil supply disruptions on record.
What happened to oil prices during the Iran war?
Brent was around $70 before the war, June futures spiked above $126 in late April 2026, and Brent was around $106 by mid-October 2026 (an estimate).
Was there a ceasefire between the US and Iran?
Yes, twice: a two-week ceasefire from 7 April 2026 and a Pakistan-mediated 60-day memorandum in June. The truce collapsed on 8 July 2026, and Iran closed the strait again.
How many people have been killed in the Iran war?
Complete figures do not exist. Reported counts include 13 US service members (as of 14 March 2026) and 1,701 Iranian civilians (as of 21 April 2026); up to 3.2 million people were displaced.
Sources
- Council on Foreign Relations, Global Conflict Tracker: Conflict with Iran (text updated 11 Sep 2026; news to 15 Oct 2026).
- Council on Foreign Relations, The Strait of Hormuz: a US–Iran maritime flash point (15 Jul 2026), citing US EIA flow data.
- Council on Foreign Relations, Trump's Iran deal reopens the strait (17 Jun 2026).
- AP via CP24 (30 Apr 2026), Brent futures.
- GlobalSecurity.org, Iran War daily update (16 Oct 2026): day count and Brent estimate.
- Casualty counts: NPR (14 Mar 2026) and HRANA via Time (21 Apr 2026), both as cited by CFR; UNHCR (displacement).