DUBAI: At least 100 Yemeni rebels and pro-government troops have been killed in the past 48 hours as fighting intensifies for the key city of Marib, military and medical sources said Wednesday.

A string of air strikes from the Saudi-led coalition targeted the Iran-backed Huthi rebels, who have stepped up their assault on Marib, the government's last northern stronghold.

Sixty-eight Huthis and 32 loyalists were killed in the latest clashes, military sources told AFP. The tolls were confirmed by medical sources.

The rebels rarely announce casualties among their own ranks, but their Al-Masirah channel reported around 60 coalition air strikes in Marib governorate in the past two days.

Hundreds of fighters have been killed this month after the Huthis renewed their campaign for the capital city of the oil-rich province.

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The Huthis initially escalated their efforts to seize Marib in February, hoping to gain control of the region's oil resources and strengthen their position in peace talks.

Marib, about 120 kilometres (75 miles) east of the rebel-held capital Sanaa, sits at a crossroads between the southern and northern regions and is key to controlling Yemen's north.

Tens of thousands of people have been killed and millions have been displaced in the war that erupted in 2014, after the Huthis seized Sanaa.

About 80 percent of Yemen's 30 million people are dependent on aid, in what the United Nations calls the world's worst humanitarian crisis.