Yemen is now closer to renewed all-out war than it has been at any point since the 2022 truce was struck, a United Nations envoy has warned.

Military activity has intensified across Yemen’s frozen front lines in recent days, with attacks causing military and civilian casualties, UN Special Envoy for Yemen Hans Grundberg told the UN Security Council on Thursday.

Fighters from the Iran-aligned Houthi group have clashed with government forces in regions of Marib, Hadramout, al-Makha (Mocha) and elsewhere.

Forces of the Aden-based internationally recognised government reported repelling a Houthi attack on Taiz, and on Wednesday the government reported carrying out artillery and drone attacks against Houthi forces across several governorates.

On Wednesday, the head of Yemen’s Presidential Leadership Council said every action undertaken by the Houthis will be met with “a comprehensive response or deterrence”.

The UN special envoy called on the parties to immediately de-escalate and work towards a robust ceasefire.

Renewed Houthi attacks on shipping in the Red Sea also risk drawing Yemen into the wider ongoing regional confrontation between the US and Iran, Grundberg warned.

Grundberg also highlighted the need to work on “economic de-escalation” for the Yemeni economy, which has been decimated by a decade of civil war.

To this end, he urged warring parties to work together to ensure commercial vessels continue to reach Yemeni ports, enable a resumption of oil exports, and restart commercial flights to and from the Houthi-held Sanaa airport.

On these issues, both sides in the conflict “have more to gain from cooperation than confrontation”, he said.

Yemen has been mired in conflict since the Houthis seized the capital Sanaa in 2014, prompting a Saudi-led military intervention the following year that spiralled into a years-long war.

The Houthis and the internationally recognised government struck a truce in 2022 that has, until now, largely held. Progress towards a lasting agreement to end the war stalled in 2023 as tensions in the wider region escalated, Grundberg said.

Deepening humanitarian crisis, cross-border attacks

The intensification of fighting in Yemen is worsening the country’s humanitarian crisis.

More than half of Yemen’s population does not have reliable access to enough food, with six million people facing “emergency” levels of deprivation that border on famine, the UN’s humanitarian chief, Tom Fletcher, told the UNSC in remarks on Thursday.

Women pay a particularly high price for the conflict, Fletcher said, with three dying every day due to preventable pregnancy-related complications.

The British government on Thursday blamed the Houthis for the humanitarian crisis and criticised the group’s deadly attacks on international shipping and direct attacks on Saudi Arabia.

The UK’s permanent representative at the UN, Sarah MacIntosh, told the UNSC that “reckless Houthi actions have triggered a serious escalation of violence in the region”, urging “the Houthis to focus on efforts to achieve peace and alleviate the suffering of Yemenis, rather than seeking to embroil Yemen in a wider regional conflict”.

On Thursday, the Houthis claimed responsibility for a drone attack on an oil refinery in Saudi Arabia’s Jazan province.

A Houthi military source told the Reuters news agency that the attack was in response to what the group described as Saudi violations of Yemeni airspace and sovereignty in Saada and Hajjah provinces.

The refinery attack was the latest in a string of drone, air and missile attacks the two sides have exchanged since the Houthis declared a blockade on Saudi shipping in the Red Sea on 20 July.