Dozens of migrants are feared to have died in a fire last weekend at a holding facility in Yemen's capital, the UN's migration agency said Friday, citing local migrant group reports.

"A statement released by a migrant group in Yemen yesterday claimed the death toll to be 43," the International Organization for Migration (IOM) said in a statement. 

"However, counterparts are now estimating the deaths to be between 30-60 people, while other unverified accounts had previously put the death toll in the hundreds."

More than 170 people were injured -- over half of them seriously -- in the blaze on Sunday at an overcrowded holding facility in Sanaa, according to the IOM.

The UN agency said on Sunday at least eight migrants and guards had died, with the actual toll likely higher. 

"IOM health and protection teams responded to the aftermath in order to urgently save lives," it said on Friday.

"Overwhelmed by the situation, the teams could not pause the emergency support that they were providing to take account of the overall deadly impact."

The IOM reiterated a call made in a previous statement urging the Huthi rebels who control the capital Sanaa to allow humanitarians and health workers to access migrants who were seriously injured in the fire.

"Access to the survivors has been a challenge since the initial response due to increased security presence at the hospitals," it said. 

It added that approximately 350 migrants, most of them from Ethiopia, were in a hangar area where the fire broke out. 

There has still been no word from Huthi rebel authorities on what caused the fire or how many people it killed. 

Despite more than six years of devastating conflict in Yemen that have created what the UN describes as the world's worst humanitarian crisis, the impoverished country is still a magnet for migrants from the nearby Horn of Africa seeking a better life in the Arab Gulf. 

Restrictions on movement imposed during the coronavirus pandemic have led to a reduction in migrant arrivals from more than 138,000 in 2019 to just over 37,500 in 2020. 

But they have also led to "thousands of migrants becoming stranded with little access to basic services or protection", according to the IOM.