Three dead seamen, one sunken ship and a looming environmental catastrophe  — Yemen's Houthis have scaled up their attacks on civilian shipping in the Red Sea.

According to the U.S. Central Command, or CENTCOM, the freighter Rubymar, which sank earlier in March after it was attacked by the Houthi militia in mid-February, has already caused an oil spill of some 29 kilometers in length. (18 miles).

So far, there is no final assessment of the environmental damage the attacks are causing.

But it it's possible that more than 7,000 barrels of oil and 22,000 tonnes of ammonium phosphate fertilizer on board the Rubymar will end up in the water, according to maritime safety expert Ian Ralby.

Despite the unclear scale of the disaster, experts already agree that the consequences would be devastating.

A large oil slick would affect the desalination plants that supply the entire region with drinking water, and the fish population could also be hit, Ralby said in his podcast "Blue Security."

This would have a huge impact on local fishing. Due to the strong currents in the narrow strait, the oil slick could be carried even further. 

Furthermore, according to US officials and the Hong Kong based telecommunications company HGC Global Communications, the anchor of the sunk Rubymar cut three to four undersea communication cables which in turn affected up to 25% of data traffic between Asia and Europe. 

Houthis thrive on Iran's 'axis of resistance'

The Houthi rebels were only recently designated as terror group by the United States and to tackle their attacks in the Red Sea, the US formed the international military coalition "Operation Prosperity Guardian" in December 2023.

The German frigate 'Hessen' is part of this operation.

However, despite targeted shelling of Houthi positions in Yemen, the alliance has not been able to stop the attacks.

This is in part because the Houthis are backed by Iran, with Tehran trying to present itself as the protective power of the Palestinians in the context of the war in Gaza.

Iran's political leadership has repeatedly threatened Israel with destruction.

"The Houthi agenda is clearly anti-American and anti-Israeli," Fabian Hinz, Middle East expert at the International Institute for Strategic Studies (IISS) in London, told DW. "It is a highly ideological Islamist movement that considers the fight against Israel to be just as important as Iran does," he added. 

Middle East expert Michael Knights from the US think tank The Washington Institute shares a similar view.

"Iran is not exercising control over the Houthis in this crisis, but rather allowing them to demonstrate their superior commitment to the objectives of the axis (of resistance — countries that consider the United States and Israel as enemies)."

The Houthis need only be let loose, not necessarily told what to do, he wrote in an analysis for the think tank's website.

Crucial military support

The extent of Tehran's support became clear in late January when US armed forces intercepted a shipment from Iran for the Houthis.

According to a CENTCOM-statement, the shipment contained components for medium-range ballistic missiles, explosives, components for unmanned underwater and surface vehicles, military communications and network equipment, assemblies for anti-tank missiles and other military components.

"The current offensive in the Red Sea and the Gulf of Aden could not be possible without Iranian assistance," Hinz told DW.

However, the Houthi attacks are not only affecting international shipping and the Red Sea.

Yemen's own population, already struggling after years of civil war, is increasingly affected by the attacks.

Yemenis bear the brunt

Negotiations between Saudi Arabia — which for years had been at the forefront of an international coalition against the Houthis — seemed to be heading towards an agreement last autumn, but progress has stalled in light of the attacks.

As a consequence, the Saudi kingdom withheld humanitarian aid it had already promised.

Rising shipping costs as a result of the attacks are also placing an enormous burden on Yemen and its population.

The country is particularly vulnerable to such fluctuations as it is almost entirely dependent on food imports. "That's why the effects of this crisis will be felt very strongly in Yemen," Hinz said.

The attacks on international shipping are therefore somewhat of a risk for the Houthis. A large proportion of people back in Yemen reject their ideology, says Hinz.

However, it remains to be seen to what extent the rise in food prices will affect the widespread anti-Israeli attitude in Yemen in the long term, he wonders.

Yet the fight against Israel continues to resonate with large parts of the Yemeni population. "In turn, the Houthis use the situation to present themselves as a legitimate resistance movement in the eyes of their supporters," Hinz added.

Analysts at the capital-based Sanaa Centre for Strategic Studies echo this thought. "For the Houthis, this is a golden opportunity to capitalize the widespread support for the Palestinian cause to raise their flagging popularity inside territories under their control, while pressing their case to the outside world that they are the only effective authority in Yemen," a report in December concluded. 

As of now, Hinz has little hope that the attacks will stop anytime soon.

"To me, it seems quite realistic that the Houthis would scale back their massive attacks if the war in Gaza were to end," he told DW, adding that "however, the Houthis are likely to regard their attacks on civilian shipping as a fundamental option, and that is unlikely to change even after a possible end of the war in Gaza."

This article was updated on March 8, 2024 to reflect the news about the damage to the undersea cables.

This article was translated from German.