Yemen's third-largest city has been under siege for nearly a decade. Rights groups say this month it got dramatically worse.

Human Rights Watch says Houthi forces used explosives on October 18 to severely damage the Hayjat al-Abd road, a critical route that is among the last ways to move food, fuel and medicine into Taiz, a city of roughly 940,000 people that the Iran-aligned group has besieged since 2016. The organization said it wrote to the Houthis on October 21 seeking an explanation and received no response, and that it could not conclusively confirm the Houthis carried out the attack — but a researcher for the group warned that civilians already facing chronic shortages now face an even sharper risk of hunger and disease. Human Rights Watch's account of the attack warns the blockade could amount to a war crime under international law.

The timing compounds an already dire month. Al Jazeera reported in early October that closures of other key roads into the city had already driven up food and fuel prices sharply, with residents describing skipped meals and burning firewood to cook as the siege tightened. Yemen's health ministry in Aden has separately warned the blockade risks a broader humanitarian and health disaster for the city.

A decade-old siege, a newly cut lifeline

Taiz has lived under some form of Houthi encirclement since the early days of Yemen's civil war, with the group controlling the highland roads surrounding a city it has never managed to fully capture. Rights organizations, including Amnesty International alongside HRW, have repeatedly pressed the Houthis to lift the blockade in recent weeks, with little visible effect. What's different now, advocates say, is that the circle of usable roads has shrunk to almost nothing.

CIVILIANS ALREADY FACE SHORTAGES OF FOOD, WATER, MEDICINE AND FUEL — AND NOW THIS

The Houthis have not publicly responded to the HRW allegation. The group, which controls much of northern Yemen including the capital Sanaa, has fought Saudi-backed and other anti-Houthi forces to a bloody stalemate for years, with Taiz sitting on the fault line between them.

Rights groups are calling for international pressure to force the road's reopening and for humanitarian convoys to be allowed through regardless of who controls which stretch of asphalt. For now, there's no indication the route has been repaired, and no timeline for when — or whether — it will be.