Iran's Defence Council — the country's highest-level security body — published a statement Monday through Iranian state outlets that represents the most explicit escalation threat of the war. The statement said the "only way for non-hostile countries" to pass through the Strait of Hormuz is "coordination with Iran." It then specified what would happen if the US attacks Iranian coasts or islands: "All access routes in the Gulf and coastal areas" would be "mined with various types of naval mines, including drifting mines deployable from the shore." The statement concluded: "In addition to the Strait of Hormuz, the whole Gulf would in practice be blocked, with responsibility belonging to the aggressor."
This is Iran saying: if you attack our coast, we mine everything. Not just Hormuz. The entire Persian Gulf.
Monday Market Reaction
South Korea's Kospi fell 6.5% on Monday — worse than the 5% drop at the Asian open earlier, and the worst single-day loss since the war began. Japan's Nikkei closed down 3.5%. Brent crude climbed above $113.40.
Simon Flowers, chairman and chief analyst at energy consultancy Wood Mackenzie, said the markets were waiting to see if the threats were "carried through." He told the BBC: "If the US does strike Iranian infrastructure, it escalates the whole intensity of the war a step further and then we'd have to see if Iran strikes back at infrastructure tit-for-tat as they've done over the last week or so."
What Mining the Gulf Means
Naval mining is one of the oldest and most effective forms of maritime warfare. A single mine costs a few thousand dollars. Clearing a mine costs hundreds of thousands to millions. The US Navy's mine countermeasures fleet — while among the world's most capable — cannot sweep the entire Persian Gulf simultaneously.
Iran's mine warfare capabilities are significant and well-documented. Iran has an estimated inventory of several thousand naval mines of various types: bottom mines (sit on the seabed, triggered by magnetic or acoustic signatures), moored mines (float at a set depth), and drifting mines (float freely and are the most indiscriminate). The Defence Council statement specifically mentioned "drifting mines deployable from the shore" — the cheapest, most scalable, and hardest-to-clear category.
Drifting mines are banned under the Hague Convention of 1907 unless they become inert within one hour of deployment. Iran has not signed the relevant protocols. Drifting mines are the maritime equivalent of cluster munitions — they cannot be precisely targeted and affect all shipping indiscriminately.
The Escalation Ladder
The sequence of escalation over 48 hours:
Saturday: Trump threatens to "obliterate" Iranian power plants if Hormuz not reopened within 48 hours.
Saturday-Sunday: Iran's parliament speaker threatens to "irreversibly destroy" Gulf energy and desalination infrastructure if power plants are struck.
Monday: Iran's Defence Council — a higher authority than the parliament speaker — escalates further: the entire Gulf gets mined. Not just Hormuz. All access routes. Including drifting mines.
Each step is a calculated raise. Trump threatened power plants. Iran raised to energy infrastructure across the Gulf. Iran then raised again to mining all Gulf waterways — which would affect not just oil but all commercial shipping, naval vessels, and maritime traffic in the region.
The "Non-Hostile Countries" Lane
The Defence Council statement included one notable conditional: the "only way for non-hostile countries to pass through the Strait of Hormuz is coordination with Iran." This creates a two-tier system: countries that Iran considers non-hostile (presumably China, India, and others not participating in the US-Israeli coalition) can still transit — but only by coordinating with Tehran directly.
This is consistent with the BBC Verify data from earlier in the war showing that approximately 100 ships had transited Hormuz in March — down 95% from pre-war levels. About a third of those were Iran-linked vessels. Several others were Chinese-owned. Ships that transited were routing through Iranian territorial waters under apparent informal agreements.
The Defence Council statement formalizes what was already happening informally: Iran controls who passes and who doesn't. The mining threat is the enforcement mechanism for countries that try to transit without permission.
What Happens to US Markets
US markets open at 9:30 AM ET Monday. Asian markets have already priced in the escalation — Kospi's 6.5% drop is the largest single-session decline of the conflict. Brent crude has moved from $106 on Saturday to $113.40 Monday morning — a 7% jump in two days.
Wood Mackenzie's Flowers identified the key variable: whether the threats are carried through. If Trump strikes Iranian power plants (as threatened) and Iran mines the Gulf (as threatened), the question becomes whether the global oil market can function at all with the entire Persian Gulf — not just Hormuz, but the full Gulf — under active mine warfare.
The answer, historically, is no. The 1987-1988 "Tanker War" during the Iran-Iraq conflict saw limited mining of Gulf waterways that damaged or sank multiple commercial vessels and required a US-led naval escort operation (Operation Earnest Will). That conflict involved partial, targeted mining. Iran is now threatening comprehensive mining of all access routes — a qualitatively different scale.
The Defence Council said the whole Gulf would be blocked. Oil is at $113. The Kospi fell 6.5%. US markets open in hours.