The ministry announced the "martyrdom of head of the government forces' military operations, Nasser al-Zubiani, who died in the line of duty while leading battles against the Iran-backed Huthi militia on the outskirts of Marib", according to Yemen's official Saba news agency.

A defence minister source had earlier told AFP that Zubiani was among 28 troops killed in clashes with the Huthis in the past 24 hours.

Government forces and the Huthi rebels have been locked for months in a fierce battle for Marib, the government's last stronghold and capital of the northern oil-rich province of the same name.

Fighting has escalated in recent weeks with thousands killed from both sides as a Saudi-led military coalition backing the government ramps up air strikes on the rebels.

The rebels began a major push to seize Marib city in February and, after a lull, they renewed their offensive in September.

The Saudi-led coalition has been reporting high death tolls in almost daily strikes against the Huthis since October.

Yemen's grinding conflict, which erupted in 2014, has displaced millions, and more than 80 percent of the population of around 30 million require humanitarian assistance.

A UN Development Programme report last month said the war will have claimed 377,000 lives by the end of the year through both direct and indirect impacts.

Nearly 60 percent of deaths will have been caused by consequences such as lack of safe water, hunger and disease, it said, suggesting that fighting will have directly killed over 150,000 people.