A Yemeni staff member of the UN Human Rights Office has died in Houthi custody after being arbitrarily held for more ​than two years, the UN human rights chief has said.

Mohammad el Shami had been detained by the Houthi militant group since 6 June 2024, UN High Commissioner for Human Rights Volker Turk ​said in a statement.

His family said they had only been notified of his death recently, more than one month after ​it occurred, and had not been informed of the cause or circumstances, ​according to Mr Turk. There was no immediate comment from the Houthis.

The UN Human Rights office said they were "utterly devastated", adding that it is a "heartbreaking loss" and the family deserves to know the truth.

Mr Turk on Saturday called for a prompt, independent and thorough investigation, and demanded the immediate and unconditional release of all other UN personnel under Houthi detention.

These include seven staff members from his office, humanitarian workers, ​and civil society members.

Yemen's prime minister condemned the death and said he held the Houthis fully ‌responsible.

He said more than 70 UN employees and dozens of humanitarian workers are still being detained.

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The group has said ​those being held were ​part of a ⁠spy network working for the US and Israel.

The Houthis have also accused humanitarian organisations of ​using their work as a smokescreen for intelligence activities, without ​providing ⁠evidence.

The Houthis seized the capital Sanaa in 2014, sparking a Saudi-led military intervention in 2015 in support of Yemen's internationally recognised government.

The conflict ⁠has ​since divided the nation, with the Houthis ​holding Sanaa and much of the north and northwest, while government-aligned forces control much ​of the south and east.

The Saudi-led coalition ​fighting in Yemen said early on Saturday that it ‌had intercepted and destroyed a drone over its oil-rich Eastern Region as attacks by Yemen's Iran-aligned Houthis group continue.

The conflict between ​the two sides has grown more intense in ⁠recent weeks, opening a destructive new ⁠front in the ​wider US-Israeli war on Iran.

Last month, there was a string of Houthi attacks on Saudi airports, including on Riyadh airport, one of which killed at least 13 people and wounded over 300.

On Wednesday, Saudi-led airstrikes struck a crowded market in northern Yemen, killing 14 people and wounding 15 others, a Houthi health official said.

The strikes hit a central market near a gas station in al Hazm, the capital of al Jawf province, around midday while it was filled with shoppers, said Anees al Asbahi, spokesperson for the Houthi-run health ministry, in a post on X.

Also on Wednesday, the Ministry of Transportation of the internationally recognised government said the Houthis had launched two ballistic missile strikes on Aden airport, according to a statement on the ministry's website.