Nearly 15,000 Yemeni Huthi fighters have been killed near the strategic city of Marib since June, sources close to the rebels said Thursday, in a rare admission of their casualties during the seven-year war.
"The air strikes launched by the Saudi-led military coalition and the battles have killed nearly 14,700 Huthis since mid-June near Marib," an official at the rebel-run defence ministry told AFP.
Another official from the same office confirmed the toll.
On the pro-government side more than 1,200 fighters were killed in the same five-month period while defending areas near Marib, two government military officials told AFP.
Marib city is the internationally-recognised government's last major stronghold in Yemen's oil-rich north.
The Iran-backed Huthis began a major push to seize the city last year.
The battle was halted multiple times due to negotiations, but the rebels renewed their attacks in February, there was a major assault in June, and an intensified push since September.
A Saudi-led coalition which intervened in 2015 to support the government has, since October 11, reported almost daily air strikes around Marib with a death toll, by their count, of around 3,800 rebels.
On Thursday the coalition said in a statement that nearly 27,000 rebels have been killed since last year in the battle for Marib.
One of the officials on the government side said that "1,250 soldiers have been killed since June near Marib," a toll confirmed by a second government military official.
AFP cannot independently verify either side's figures.
The war has led to what the United Nations calls the world's worst humanitarian crisis. Tens of thousands of people have died and millions have been displaced.
The loss of Marib would be a major blow for the government and would strengthen the rebels' position in future peace negotiations, according to experts.
This week a convoy of Yemeni army reinforcements arrived on the southern front of Marib to join loyalists fighters.
The troops in red berets rode in pickup trucks bearing the Yemeni flag.
As fighting continues on that front the Huthis on Friday took control of a large area south of Hodeida, a Red Sea port where the warring sides agreed on a ceasefire in 2018, after loyalist forces withdrew.
The United Nations Mission to support the Hodeida Agreement (UNMHA) said on Monday that the latest developments "represent a major shift of the front lines", a possible reference to the Marib front.
The Saudi-led coalition intervened in Yemen in early 2015 to shore up the government after the Huthis seized the capital Sanaa months before.