Yemen Situation Update: January 2024

US-led strikes trigger a fourth phase of escalating Houthi attacks

Houthi attacks on international shipping lanes continued through January, prompting a military response from the United States for the first time since the reopening of the Red Sea front in October. Far from deterring Houthi forces, US-led strikes strengthened the group’s resolution and spurred yet another escalation of the attacks, with an increasing number of ships in the Red Sea and Gulf of Aden falling under missile and drone attacks. 

Looking at developments over the past three months, a series of step-changes in the Houthi maritime attacks have led up to the US military intervention. In January, the Red Sea crisis entered what can be described as a fourth escalatory phase, in which the Houthis and a US-led coalition are engaged in a retaliatory cycle from which neither side seems eager to back down. US-led strikes follow a pattern similar to the early stages of the Saudi-led Coalition’s bombing campaign, suggesting that this trend may become more apparent the longer the US-led operation continues.

Houthi Red Sea attacks persist despite warnings and international condemnation

The Red Sea crisis intensified in January. Following the killing of 10 Houthi fighters by US naval forces during a failed hijacking in the Red Sea in late December, Houthi leaders warned that there would be a military response. The group dismissed a subsequent final warning from the international community, detonating an unmanned surface vehicle, also called a ‘drone boat,’ near international shipping lanes and launching a wave of drones and missiles at US and United Kingdom warships. 

The United Nations Security Council passed a resolution on 10 January strongly condemning Houthi attacks and reiterating the right of UN member states to defend their ships in international waters. The next day, the Houthis fired a missile onto shipping lanes in the Gulf of Aden for the first time, just hours before US-led strikes hit Houthi military targets in six governorates, killing eight Houthi fighters (see map below). The sides have since continued to exchange tit-for-tat strikes in the Red Sea, Gulf of Aden, and Yemen. 

Evolution of Houthi maritime attacks

Prior to January 2024, Houthi maritime attacks evolved through three distinct phases. The fourth phase, preceded by the launch of Operation Promised Conquest and Holy Jihad, began on 9 January when the group claimed to target a US warship for the first time (see graph below). This was quickly followed by the first round of US-led strikes on 12 January, as part of Operation Poseidon Archer. In response, Houthi forces declared US and UK commercial and naval vessels as military targets, extended the range of their attacks to the Gulf of Aden, and used new weapon systems to target ships. 

Between 9 and 31 January, the Houthis have conducted 21 attacks on ships, compared to 15 in the previous three weeks. Of the incidents since the start of Operation Poseidon Archer, the group has claimed that six have ties with US- or UK-based owners or operators, while none have clear identifiable links to Israel; there have been no confirmed Houthi attacks toward Israel since 26 December. Most of the Houthi attacks in the previous phases of the maritime operations targeted container and dry bulk carriers. In January, however, the group struck two oil tankers, including an attack on the Marlin Luanda on 26 January that set off a fire that lasted for several hours. This attack was the most destructive incident to date.

The attacks also expanded to the Gulf of Aden, home to 11 of the 21 maritime attacks recorded since 9 January. The group claimed that all of the targeted ships in the Gulf were US- or UK-linked. Houthi forces also changed the modes of attack, using explosive-laden drone boats, along with a range of tested anti-ship ballistic and cruise missiles. Although the success rate of the evolving attacks against naval warships has not improved, US officials reported that a cruise missile came within a mile (1.5 kilometers) of the USS Gravely on 30 January — the closest a Houthi projectile has come to a US warship. 

US-led strikes Yemen to weaken Houthi attacks

In an attempt to deter the Houthi attacks, the US and the UK, with support from four other countries, launched Operation Poseidon Archer. In January, the alliance carried out 11 waves of strikes on military targets across Houthi-controlled areas in Yemen (see map below). According to the US Central Command, these strikes destroyed or degraded over 27 missile and drone launch and deployment facilities, more than 21 missiles, and 10 drones. The operation continued into February, with another 11 rounds of strikes in the first half of the month.

The US-UK operation is aimed at weakening the Houthis’ capabilities to carry out complex attacks on international shipping rather than inhibiting the group’s military capacity altogether. The Biden administration has thus signaled its readiness to conduct a sustained and, at the moment, open-ended campaign against the Houthis. 

To this end, the US-UK strikes have been of two types. The first type involves pre-planned degradation barrages on stationary military assets, including radars and underground weapon storage bunkers. These attacks are usually more numerous and carried out during the quieter hours of the night. A second type includes more limited dynamic targeting of pop-up mobile weapons systems. These attacks have been more frequent, with 15 missiles and launchers bombed before they could fire at ships. This approach is intended to degrade the Houthis’ ability to carry out more maritime attacks while minimizing casualties — both combatant and civilian — to avoid further escalating the situation. 

A repeat of the 2015 Saudi-led bombing campaign?

The latest US strikes in the region have resembled the 2015 Saudi-led Coalition’s intervention in Yemen, which Crown Prince Mohammed bin Salman allegedly said would only need a few weeks to remove the Houthis. However, despite seven years and around 23,000 airstrike events, the Houthis still control much of the country and have been able to develop a formidable military arsenal, with support from Iran and Hezbollah. This outcome suggests that the limited nature of the US-led strikes under Operation Poseidon Archer is unlikely to weaken the group sufficiently enough to end their maritime attacks.

ACLED records 29 US-UK airstrike events in Yemen in January, resulting in at least eight reported fatalities. By comparison, the first three weeks of the Saudi-led Operation Decisive Storm saw 395 airstrike events, resulting in over 500 fatalities. Saudi-led airstrikes hit at least 200 known military sites in that initial three-week period, several of which have also been among the first targets of the US strikes. Al-Daylami Air Base in Sanaa city was the first location bombed in both operations, and seven other sites were also on both sets of initial targets. Nine of the locations targeted by the US-UK strikes were previously hit by 419 airstrikes in the Saudi-led air war between 2015 and 2022 with up to 1,336 individual projectiles, as recorded by the Yemen Data Project. However, this bombardment did not stop these locations from still being used as military sites. 

In 2015, the Houthi response to the bombings was belligerent, and that has also been the case in 2024. The Saudi-led strikes failed to halt the advance of Houthi forces into southern Yemen — which required a United Arab Emirates-led ground operation to push them back — nor degrade their ability to carry out cross-border attacks. Following the US-led strikes, the Houthis have escalated and expanded their attacks on international shipping lanes while also increasing their attacks on the frontlines in Yemen. As a result, the longer the bombing campaign continues, the more resolute the Houthis may become — similar to the events of 2015.

Impact of the US-led strikes

The US-UK strikes have had a limited impact to date. The military response may have been aimed at reassuring shipping firms but, nevertheless, more vessels have been rerouted away from the area. According to maritime intelligence firm Lloyd’s List, commercial shipping transiting the Red Sea has decreased at a greater rate since the start of the US-led strikes on 11 January than during the first two months of the Houthi attacks. The recent Houthi attacks on oil tankers have also increased tanker rates and diesel prices, while freight rates have jumped to levels not previously seen outside of the COVID-related spike. 

Yet, the Houthis have used the US-UK attacks to galvanize supporters domestically. ACLED records nearly 400 pro-Palestine rallies in January, a 65% increase from December. Houthi leaders have used the Israel-Gaza conflict and confrontation with the US and UK to rouse support, as well as to continue to recruit and mobilize additional forces, allegedly including thousands of child soldiers since October, in preparation for a potential renewal of hostilities.

Looking forward

• The Houthis and the US-led coalition are continuing to trade strikes, making a further escalation more likely than a reduction in military activity. The largest round of joint US-UK strikes yet hit Houthi targets on 3 February, prompting more missile launches at allegedly US- and UK-related ships in the Red Sea and Gulf. As has been the trend since October, these operations will likely steadily expand in the targeting and types of attacks if regional tensions keep rising, potentially extending to Houthi strikes on US and UK military assets in the region.
• The US is pursuing a three-pronged ‘military-sanctions-diplomacy’ strategy to compel the Houthis to stop their attacks. The strategy includes cutting off weapon supplies from Iran, sanctioning their leadership and affiliated entities, and engaging in back-channel diplomacy. This strategy may only bear fruit in the long term, and in the short term it has prompted further Houthi backlash. 
• The Houthi leadership has taken advantage of the US-UK strikes to boost recruitment and support at home. They also retaliated politically by ordering all US and UK nationals working for the UN and INGOs to leave the country. The group will likely introduce additional measures in lock-step with any international sanctions, further restricting the operating environment in Yemen.
• The US military action has not encouraged shipping firms to resume transiting the Red Sea, and global trade will not return to normal as long as the Houthi threat remains. Most international shipping companies are re-routing their vessels away from the Red Sea or finding alternative means of transport.

• The Houthis insist that only a ceasefire in Gaza would halt the attacks, but even this is not certain. Alternatively, they may settle for allowing humanitarian aid into Gaza. The group suspended their Red Sea attacks during the short-lived truce in November, although the last stoppage came before the US-UK strikes. It is uncertain whether the recent escalation has changed that calculation.
• US and UK officials have denied preparing for an international intervention, which remains an unlikely scenario. Yet, hostilities on the ground are increasing, and the Houthis are testing the resolution of the forces aligned with the internationally recognized government (IRG). The IRG seeks international military support to push the Houthis away from coastal areas, but US and UK officials have ruled out putting ‘boots on the ground’ in Yemen. It is more likely that Houthi forces will use the regional escalation as a justification to try to seize key sites in Shabwa and Marib, thus derailing the ongoing truce talks in Riyadh.