1 of 2 | Several Red Cross members attend to a migrant upon his arrival at the port of Arrecife on Lanzarote island in the Canary Islands, southwestern Spain, on July 14. Photo by Adriel Perdomo/EPA

July 21 (UPI) -- The U.N. refugee agency announced Tuesday that 144 refugees and migrants have died or were missing after "tragic maritime incidents" off the coast of Mauritania last week.

Matthew Saltmarsh, spokesman for the U.N. High Commissioner for Refugees, said in a press briefing in Geneva, Switzerland, that those lost were attempting the sea journey from West Africa to Europe.

Three rescue operations between July 14 and 18 brought 387 people safely ashore in Nouadhibou, Mauritania, Saltmarsh said. The survivors were from multiple countries.

One of the boats rescued on July 18 had 38 survivors, with 143 dead or missing. The passengers spent nearly 25 days stranded on the ocean after leaving The Gambia and trying to make it to Spain. Among the survivors were two children who lost all their family members at sea.