Iran is in possession of an estimated 5,000 to 6,000 naval mines, a report from the US Congress published last year shows.
The report, which was published in the wake of a 12-day conflict between Iran, Israel and the US in June 2025, explored the impact of that flareup on oil and gas markets in light of interruptions to the Strait of Hormuz.
It states that Tehran was believed to have an arsenal of more than 5,000 naval mines in 2019. Estimates in 2025 put this number as slightly higher at around 6,000.
In Iran’s possession are a variety of the underwater weapons, according to the US report, including limpet mines, which can be attached to a ship’s hull; moored mines, which float under the surface of water and explode when they come into contact with a ship, and “bottom” mines, which rest on the sea floor and detonate when they detect a nearby vessel.
Some context: Two people familiar with US intelligence told CNN that Iran has begun laying mines in the Strait of Hormuz, the world’s most important energy chokepoint that carries about one-fifth of all crude oil.
The mining is not extensive yet, with a few dozen having been laid in recent days, the sources said. But Iran still retains upward of 80% to 90% of its small boats and mine layers, one of the sources said, so its forces could feasibly lay hundreds of mines in the waterway.
US President Donald Trump said in a post on Truth Social on Tuesday that “if Iran has put out any mines in the Hormuz Strait, and we have no reports of them doing so, we want them removed, IMMEDIATELY!”
CNN’s Natasha Bertrand contributed reporting.