Four boats carrying migrants from Africa have capsized in waters off Yemen and Djibouti, leaving at least two people dead and 186 missing, according to the United Nations migration agency.

A spokesperson for the International Organization for Migration (IOM) said on Friday that two of the boats capsized off Yemen late on Thursday.

Tamim Eleian said two crew members were rescued, but 181 migrants and five Yemeni crew remain missing.

The IOM chief of mission in Yemen said the majority of those onboard were believed to be Ethiopian migrants and five were thought to be Yemeni crew members. At least 57, from both boats, were women.

“We are working with authorities to see if we can find any survivors, but I’m afraid we may not have any,” Abdusattor Esoev told the AFP news agency.

Two other boats capsized off the tiny African nation of Djibouti about the same time, Eleian  said. Two bodies of migrants were recovered, and all others on board were rescued.