Julie Lenarz is a Director at the London-based Human Security Centre. 

As the battle for Hodeidah – the main port in Yemen and distribution point for more than 70 per cent of aid and medical supplies reaching the war-torn country – intensified last week, efforts by the United Nations to bring the war to an end through diplomacy have reached a critical juncture.

The Houthis, an Iranian-aligned rebel group which has occupied the city since October 2014, have used the grace period negotiated by the UN’s envoy Martin Griffiths with the Saudi-led coalition of Arab states to further entrench their position in Hodeidah and mobilise the support of their state sponsors.

Sana’a, Yemen’s capital, is one of four Middle Eastern centres of power under Tehran’s influence – along with Damascus, Baghdad, and Beirut – and Hodeidah is Iran’s main point of entry to the conflict, allowing them to arm the Houthi rebels with Qassam rockets and other weaponry.

According to the Arab Coalition, 83 ballistic missiles were fired by the Houthi militia at Saudi Arabia from Yemen in 2017. Dozens more were launched this year, targeting oil refineries and shipping stations, and in March debris killed an Egyptian civilian in Riyadh. The Houthis made clear they respect no “red lines” in the conflict when they announced in December that they had aimed at a nuclear reactor in Abu Dhabi, unsuccessfully as it turned out.

“We question why Iran is spending significant revenue in a country with which it has no real historical ties or interests, rather than using its influence to end the conflict for the good of the Yemeni people,” Boris Johnson, then Foreign Secretary, and Penny Mordaunt said in a joint statement in March.

Two weeks ago, the rebel movement claimed that it had attacked the Abu Dhabi airport in the United Arab Emirates with a drone. It later turned out to be a Houthi hoax, but the intent was telling. Saudi Arabia had announced a day earlier the temporary cessation of all oil shipments through the Bab el-Mandeb Strait – one of the world’s most important commercial shipping lanes, connecting the Red Sea to the Gulf of Aden – after the Houthis fired on two large crude carriers operated by Saudi National Shipping Corp. Qassem Soleimani, the leader of the Iranian Revolutionary Guards (IRGC), followed up with a speech threatening an escalation of conflict in the area.

More concerningly, it appears that the Houthis fired a mortar at a popular fishmarket and hospital in Hodeida city last Thursday, blaming Coalition airstrikes in an attempt to undermine international support on the day the UN Special Envoy was due to update the Security Council. The deceit was exposed when mortar shells were discovered at the scene and satellite footage showed a blast radius inconsistent with aircraft weaponry. But dozens of civilians were killed and a critical anti-cholera hospital damaged.

Since taking control of Hodeidah, the Houthi rebels have been levying extortionate taxes on aid shipments and often have diverted desperately-needed humanitarian supplies to their frontline troops. According to a Human Rights Watch report from last year, the Shiite movement has “imposed onerous restrictions on aid workers, interfered with aid delivery, and restricted the movement of ill civilians” – a reckless policy that is threatening the lives of millions.

But in the past two months, since Griffiths was given time by both sides to reach a peaceful settlement, Houthi activity in the city has intensified, with disastrous consequences for its citizens. Reports of trenches and landmines in civilian areas have concerned NGOs, who believe this will disrupt ground water systems and deepen a cholera epidemic.

Civilians have been recruited to defend the city on the frontline, some of them children, even though the Houthis have no ethnic or cultural claim to represent the city; they are a small tribe from the North representing barely one in twenty Yemenis.

It’s clear that the Houthis and Iran are exploiting the peace talks over Hodeidah. Without a deadline, they have no incentive to agree to anything – the status quo suits them too well. They have made it clear that there are no terms or threats which will convince them to release this city and port from their grip.

They are holding Hodeidah hostage.

The Coalition appears to face a difficult choice – take action and the risks associated with it, or face another 18 months of gridlock in Hodeida, almost certainly leading to a significant deterioration of the humanitarian situation. Few countries would envy a situation like this with a neighbour and ally, but the writing, it seems, is on the wall.

The rules of engagement are clear. UN Security Council Resolution 2216 explicitly demands that the Houthis “withdraw from all areas seized during the latest conflict”, including Hodeidah. The only way to end the war quickly is to cut off the Houthi supply line by ensuring control of the port returns to the internationally recognised Yemeni Government, or is placed under UN supervision.

As events of the past few weeks have tragically made clear, only this outcome would allow for the improved flow of desperately needed aid in the short term and, in the medium term, force the Houthis back to the negotiation table. It’s the best chance to end the world’s most deadly conflict.