This article is based on content originally published on our partner platform Seerist, the augmented analytics solution for threat and risk intelligence professionals.
From 15-17 March, the US launched a series of airstrikes against assets and infrastructure belonging to Yemen’s Houthi rebel movement. Compared to previous US strikes, these targeted a broader range of Houthi targets. What are the implications for commercial shipping in the region?
- The Houthis are very likely to seek to renew attacks on vessels affiliated with the US. This affiliation includes flag or commercial links like ownership, operator or management.
- Because there is a lack of obvious US, UK or Israeli targets in the waters currently, the Houthis may look for tenuous links or even randomly target vessels and claim links.
- Should additional US strikes (which are likely) increasingly focus on sensitive Houthi targets critical to the group’s survival, such as senior leadership, this could prompt the group to shift from limited sea denial to an attempted (though unlikely) total blockade of the Bab el-Mandeb Strait via randomised attacks.
- Related threats from US officials to attack Iranian vessels providing support to the Houthis risk retaliatory action by Tehran against US-affiliated commercial ships.
Strikes
These were the first strikes on Houthi assets under US President Donald Trump and were more escalatory than those carried out during the Biden administration. In addition to targeting weapons sites, US forces also targeted key sites in the capital, Sana’a, and Sa’adah, where the Houthi leadership is believed to reside. On 16 March, US National Security Adviser Mike Waltz said that the strikes “hit multiple Houthi leaders and took them out”. Control Risks has not been able to verify which figures were killed in these strikes.
In response, the Houthis claimed to have attacked the USS Harry Truman carrier strike group with 18 ballistic missiles and a drone in the northern Red Sea on 16 March and again on 17 March. A US official told ABC News that the Houthis fired 11 drones, all of which were intercepted by US aircraft, and one ballistic missile, which fell well short of the strike group.
Among other assets, the US strikes on 17 March targeted the Galaxy Leader – an Israeli-owned car carrier that the Houthis hijacked in the Red Sea in November 2023 (it has since been declared a Constructive Total Loss) – but may have been used by the Houthis for surveillance and targeting purposes since.
Multiple US officials have stated that further airstrikes are likely over the coming weeks.
Immediate implications
As forecast by Control Risks, US strikes on the Houthis have prompted the group to declare US-linked vessels in the southern Red Sea and Gulf of Aden targets for attack once again.
At the time of writing, Control Risks is not aware of a statement from the Houthis’ Humanitarian Operations Coordination Center (HOCC) – which the group uses to communicate with commercial shipping – that outlines the group’s (re-)expanded target list in detail. Such a statement was issued on 19 January, after which the Houthis narrowed their transit “ban list” to Israeli-flagged or “fully” Israeli-owned vessels. Nevertheless, based on other statements from Houthi officials, the Houthis will very likely seek to target any vessel affiliated with the US through flag or commercial links such as ownership, operator, or management.
Houthi statements immediately following the US strikes referenced responding to “British aggression”, but a subsequent speech from Houthi leader Abdul Malik al-Houthi did not. However, Control Risks assesses that the Houthis would target a UK-affiliated ship.
These developments follow an HOCC statement issued on 12 March announcing a “new” ban on “Israeli” ships in the Red Sea after the Houthis’ demand for Israel to resume humanitarian aid into Gaza (Palestinian Territories) was not heeded. This was unlike the 19 January statement, which specifically excluded vessels that were Israel-bound, were managed or operated by Israeli individuals or entities, were “partially” owned by Israeli individuals or entities, or which belonged to a fleet where other vessels (if not the targeted vessel itself) have serviced or are currently servicing trade with Israel. In practice, particularly since the US strikes, Control Risks assesses that all the above are now Houthi targets again.
However, because there is a lack of obvious targets fitting this profile in the southern Red Sea, the Houthis may become desperate in their need to show force in response to the US strikes and after their failure to strike the USS Harry Truman strike group. The group could look for tenuous links between passing ships and the US, the UK or Israel – or even randomly target a vessel and claim it has such links.
Bab el-Mandeb shutdown not imminent
Beyond an immediate response, additional US strikes deemed existential to the Houthis’ survival – such as the targeting of key leadership officials, including al-Houthi – could prompt the group to begin indiscriminately attacking ships in the Red Sea on a broader scale to shut down the Bab el-Mandeb Strait.
Since November 2023, when the Houthis began their current maritime campaign, the attacks have been highly unpredictable but not indiscriminate – partly to avoid deterring ship owners and operators from calling at the Houthi-controlled port of Hodeidah through which vital supplies are delivered to the people of Yemen. If the group were under existential threat, its calculations might change, and it may seek to use an attempted blockade to generate international pressure in its favour.
Targeting of Iranian vessels
Related threats from US officials to attack Iranian vessels providing intelligence or military support to the Houthis risk retaliatory action by Tehran against US-affiliated commercial ships. Waltz said that Iranian vessels off Yemen’s coast, alongside other Iranian targets onshore “will be on the table” for future targeting. Iran’s Islamic Revolutionary Guards Corps Navy (IRGCN) uses ostensibly civilian ships to provide support to its proxies.
Under Biden, the US refrained from physically assaulting one such vessel assisting the Houthis with their maritime attacks, the Iranian spy ship Behshad, but did launch a cyber attack against it in February 2024. Waltz’s public statement removes any element of plausible deniability for the US and gives the greenlight for Israel to attack any such vessel. Israel is believed to have conducted a limpet mine attack against another IRGCN vessel in the Red Sea assisting the Houthis, the Saviz, in April 2021.
We continue to assess that neither the US nor Iran are seeking an open war with each other. Iran would likely use calibrated physical strikes against US-linked ships, designed to avoid casualties or major vessel damage, in response to any US attacks that kill Iranian sailors. Discreet placing of limpet mines or a drone strike would be the preferred Iranian tactics: these are more deniable and less likely to result in casualties that could provoke an even greater US response.