CAIRO (AP) — A fire broke out Sunday in a detention center for migrants in Yemen’s capital, killing at least eight people and injuring more than 170 others, the U.N. migration agency said.

The International Organization for Migration said the cause of the fire at the detention center, south of the city of Sanaa, was not immediately clear. Over 90 wounded migrants were in serious condition, it said. The death toll could be much higher, it said.

The detention center is run by the Houthi rebels, who have controlled the capital since the outbreak of Yemen’s conflict more than six years ago. The rebels said civil defense teams managed to extinguish the fire and that investigations were ongoing to determine its cause.

A U.N. official said the fire broke out in a hangar close to the main building of the detention center, which was housing more than 700 migrants.

Most of the migrants were arrested in the northern province of Saada, while trying to cross into Saudi Arabia, said the official who spoke on condition of anonymity because she was not authorized to brief the media.

“But this is just one of the many dangers that migrants have faced during the past six years of the crisis in Yemen,” said Carmela Godeau, IOM's regional director for MENA region, in a tweet.

The narrow waters between the Horn of Africa and Yemen have been a popular migration route despite Yemen’s ongoing conflict. Tens of thousands of migrants, desperate to find jobs as housekeepers, servants and construction workers, try to make their way through Yemen every year to the oil-rich Gulf countries.

Some 138,000 migrants embarked on the arduous journey from the Horn of Africa to Yemen in 2019, but this number decreased drastically to 37,000 last year because of the coronavirus pandemic. Over 2,500 migrants reached Yemen from Djibouti in January, according to IOM.

Those migrants are vulnerable to abuse by armed trafficking rings, many of them believed to be connected to the armed groups involved in the war. Earlier this month, at least 20 migrants were dead after smugglers threw 80 overboard during a voyage from Djibouti in East Africa to Yemen, according to the IOM.