UN Secretary General Antonio Guterres has called for the 'immediate and unconditional release' of 11 UN staff arrested by Houthi authorities in Yemen.

The workers were detained by security forces in raids on the World Food Programme (WFP), children's charity UNICEF, and the World Health Organization (WHO), news agencies and the UN reported.

Sunday's raids took place in the capital, Sanaa, and the port city of Hudaydah, as noted by UN Special Envoy for Yemen Hans Grundberg.

Grundberg commented that the Houthis had previously been holding 23 other UN workers arrested since 2021.

Houthi authorities have not released any comments regarding the arrests.

In a statement, Guterres stated that he 'strongly condemn[s] the arbitrary detentions of at least 11 UN personnel' by the Houthis, denouncing the forced entry into UN premises and the seizure of property.

The motivations behind the arrests remain unclear, yet the UN’s staff and aid workers are crucial in delivering assistance to Yemenis enduring one of the world's gravest humanitarian crises.

It was reported that one individual previously arrested died in detention earlier this year.

Furthermore, the Houthis have detained approximately 20 Yemeni employees of the US embassy for the past three years.

Despite ongoing engagement and assurances sought over the last year, Grundberg highlighted the persistent arbitrary detention of UN staff and civil society workers, stating, 'These actions severely hinder broader efforts to deliver assistance and advance peace in Yemen.'

Earlier this year, the UN suspended all movement in Houthi-controlled areas of Yemen following multiple detentions of its personnel.

The recent arrests occur amidst heightened tensions following an Israeli attack that killed the Houthi prime minister and other senior officials. This marked a significant response by Israel in retaliation against missile attacks launched by the Houthis in support of the Palestinians in Gaza, where an ongoing conflict with Hamas continues.

The Iran-backed Houthis have controlled Yemen's capital and the north-west region since they ousted the internationally recognized government in 2015 around the time of a civil war, leading to over 150,000 deaths and creating a humanitarian crisis marked by displacements of approximately 4.8 million people and 19.5 million in need of aid.