The International Organization for Migration (IOM) called on Tuesday for the release of more than 3,000 migrants, mainly Ethiopians, who it said remain held in inhumane conditions in two detention centres in southern Yemen.
The detentions began two weeks ago in the city of Aden and the neighbouring province of Lahj, which are under the control of the internationally-recognised government backed by Saudi Arabia and the United Arab Emirates.
The coalition is fighting Iran-aligned Houthi rebels who control Sanaa, the capital, and other major urban centres after more than four years of war.
"Some 3,000 migrants continue to be held in two temporary detention sites in Yemen's Aden and Abyan governorates," IOM spokesman Joel Millman told a news briefing in Geneva.
They include about 2,500 held in a football stadium in Aden, where aid workers are fighting disease outbreaks, he said.
IOM said last week that on April 30, guards fired on migrants detained at Aden sports stadium, two of whom suffered gunshot wounds, leaving a teenage boy likely paralyzed for life. It had no further information on the incident on Tuesday.
"IOM remains extremely concerned for the people being held in inhumane conditions in Aden and Abyan," Millman said.
The IOM was talking to the authorities to try to get them released, he added.
The U.N. migration agency had received reports that in recent days more than 1,400 people detained at a military camp in Lahj were released, he said. At least 14 migrants have died of an outbreak of acute watery diarrhoea in Lahj, where IOM is treating some 70 former inmates, he said.
IOM is planning to evacuate 237 Ethiopians to Addis Ababa under its voluntary repatriation programme, he said.
Thousands of migrants arrive in Yemen every year, mostly from the Horn of Africa, driven by drought and unemployment at home and lured by the wages available in the Gulf.
"Thousands of migrants are stranded in other locations throughout Yemen," Millman said.