Iran-backed non-state armed group; designated terrorist organisation (US 2024); direct threat to NATO naval operations and global shipping; demonstrated anti-ship and anti-aircraft capability
Data vintage: 2025-01-01 Source: SIPRI / IISS / CRS
Assessment Summary
The Houthis (Ansar Allah) control northwest Yemen including Sanaa and the Red Sea coast. Since October 2023 they have attacked over 90 commercial vessels and conducted strikes on Israel using ballistic missiles, cruise missiles, and drone swarms — demonstrating the most advanced military capability ever exercised by a non-state armed group. Their attacks have disrupted ~15% of global shipping traffic, forcing major rerouting around the Cape of Good Hope at an estimated $10B+ in additional shipping costs.
Key Assessment
The Houthi campaign against Red Sea shipping is unprecedented for a non-state actor and has demonstrated the ability to threaten NATO naval assets. Their use of ballistic missiles against Israel has been intercepted but forces continuous defensive expenditure of expensive interceptor missiles. US/UK strikes have degraded but not stopped their launch capability. They benefit from Iranian missile technology, ballistic missile expertise, and IRGC training.
Threat Indicators
Red Sea shipping attacks
—Ongoing / high tempo
Iran resupply
—Active (via Oman/Iraq routes)
US/UK strike degradation
—Limited effect on launch rate
Territorial control
—Stable (NW Yemen)
Ballistic missile inventory
—Partially depleted, resupplied
Capability Domains
Anti-Ship / Maritime
High
C-802 anti-ship missiles (Iranian-supplied). 17 Shaheed anti-ship loitering munition. 90+ ships struck or threatened since Oct 2023. Sea mines deployed.
Ballistic Missiles
High
Burkan-2H (modified Scud-C); Hatem 1/2; Toofan. Demonstrated range to Israel (~2,000 km). Used in saturation attacks requiring expensive interceptors.
UAV / Loitering Munitions
High
Shahed-136/138 (Iranian-supplied loitering munitions). Samad-3 jet UAV. Waheid suicide boat. Large swarms employed vs. US/coalition naval assets.
Irregular / Ground Warfare
High
~150,000–200,000 fighters. Combat experience from 9-year civil war. Significant resilience to air campaign attrition.
Air Defence
Moderate
Man-portable air defence (MANPADS). Radar-guided AAA. Shot down US MQ-9 Reapers. Limited but demonstrated counter-air capability.
Cruise Missiles
High
Quds-3 (derived from Iranian Soumar/Ya Ali). ~1,500 km range. Used in attacks on Israel and Saudi Arabia. Difficult to detect at low altitude.
Capability Radar
Defence Expenditure
SIPRI Military Expenditure Database
Key Modernisation Programs
Red Sea Shipping Campaign
Active (Oct 2023–)
Systematic attacks on commercial shipping in the Red Sea and Gulf of Aden. Over 90 vessels struck or threatened. Forced global shipping rerouting adding ~14 days and $1M+ per voyage around Cape of Good Hope.
Ballistic Missile Expansion
Ongoing
Iranian-supplied ballistic missile technology and IRGC technical advisers enabling expanded range and accuracy. Hatem-2 MRBM reaches all of Israel from Yemen.
Anti-Submarine Capability
Development
Sea mines and explosive boats assessed as potential sub-surface threat. Iranian expertise in mine warfare being transferred.
Order of Battle Summary
IISS Military Balance
Strike Capabilities
Ballistic missiles
~300–400 est.
Burkan-2H, Hatem-1/2, Toofan; range up to 2,000 km
Cruise missiles (Quds-3)
Significant stockpile
~1,500 km range; low-level flight; threat to Red Sea shipping and land targets
Shahed loitering munitions
High-volume supply
Iranian-supplied; saturation attacks on naval vessels and Israel
C-802 anti-ship missiles
Operational
Iranian-supplied; sea-skimming; threat to commercial and naval vessels in Red Sea
Explosive-laden boat drones
Active
USV swarms; used against merchant vessels; difficult to intercept
Ground Forces
Total fighters
~150,000–200,000
Significant combat experience from civil war; motivated; tribal loyalty
Artillery
Significant
Towed and self-propelled; large captured Yemeni armed forces inventory
Armoured vehicles
Captured fleet
Significant T-54/55/72 tanks and APCs from Yemeni army
Military Doctrine & TTPs— Tactics, Techniques & Procedures · NATO Planning Relevance
Houthi strategy imposes economic costs on adversaries through maritime trade disruption rather than territorial conquest. Cheap Iranian-supplied drones, missiles, and mines hold high-value shipping at risk across a vast maritime area. The Red Sea campaign (2023–2025) is the most significant demonstration of this doctrine, showing that a sub-state actor with Iranian backing can effectively disrupt a major global trade chokepoint without triggering a decisive military response.
Key TTPs
▸One-way attack drones (Samad-3) for economy-of-force strikes on commercial shipping
▸Anti-ship ballistic missiles (Burkan-2H derivative) at standoff range
▸Maritime mine-laying in contested approach channels
▸Drone/missile saturation to exhaust interceptor magazines and impose cost
▸Media strategy exploiting civilian casualty narrative to constrain adversary response
▸Underground and cave launch infrastructure to survive counter-strike
Known Vulnerabilities
▸Entirely dependent on Iran for advanced missile and drone components
▸Limited air defences vulnerable to sustained Allied precision strikes
▸Terrain advantage limits but does not eliminate effective air campaign
▸No ability to project force beyond maritime/missile domain
A2/AD Approach
Sea denial zone extending 1,500+ km from Yemen using Samad-3 drones and Burkan missiles. Forces adversary naval vessels into sustained high-cost defensive posture. Fortified mountainous terrain in Yemen limits effectiveness of air campaigns against distributed launch sites.
NATO Planning Implication
The Red Sea campaign directly damages NATO European economies (energy imports, Suez trade) without triggering Article 5 — a successful sub-threshold economic coercion model. Sets precedent for proxy sea-denial operations as a template for Iranian strategy against Allied interests. Demonstrates that Alliance lacks a decisive response framework for proxy maritime coercion.
Procurement & Arms Transfers— open-source reporting · SIPRI · UN Panel of Experts · Reuters · AP
2024-02DeliveryAnti-Ship Missiles
Receiving
Iranian Anti-Ship Missile and Cruise Missile Technology Transfer
Iran (IRGC Navy)→Houthis
Houthi forces deployed Iranian-derived Quds-class anti-ship cruise missiles (C-802/Noor derivatives) in their Red Sea campaign, striking multiple commercial vessels and warships from 2023 onwards. US Navy destroyers conducting intercepts recovered Iranian-manufactured components. The anti-ship capability — beyond anything Houthis could produce domestically — derives entirely from Iranian transfer. The campaign disrupted approximately 15% of global shipping through the Suez Canal.
Source: US CENTCOM public statements / UKMTO / UN Panel of Experts / Reuters
UN Panel of Experts reports (S/2023/833 and preceding) document Iranian-origin components in Houthi ballistic missiles including propellant chemistry, guidance electronics, and structural elements matching Iranian Fateh-110 and Shahab designs. Supply runs via Yemen's western coast and smuggling networks. Despite international naval operations including Operation Prosperity Guardian, IRGC supply continued through 2024–2025 sustaining the Red Sea campaign.
Source: UN Panel of Experts on Yemen S/2023/833 / US CENTCOM / Reuters
2024-01ReportedUAS / Loitering Munitions
Receiving
Samad-3 Long-Range UAV and Shahed-Derived Drone Deliveries
Iran (IRGC Aerospace)→Houthis
Iran supplied Houthi forces with Samad-3 long-range fixed-wing attack drones (~1,500 km range) used in the September 2019 Abqaiq attack and throughout the 2023–2025 Red Sea campaign. Shahed-136-derived variants have also been supplied. UN experts confirmed Iranian components in recovered drone wreckage. The drones provide Houthis with a long-range strike capability against targets in Israel, Saudi Arabia, and the UAE far beyond domestic production capacity.
Source: UN Panel of Experts on Yemen / US CENTCOM / Janes / Reuters