40 migrants and refugees have reportedly drowned after a boat carrying them sank off the coast of Mauritania, leaving only one survivor, the United Nations refugee agency UNHCR has reported.

According to the report, the perilous sea passage from West Africa to the Canary Islands was once a major route for migrants seeking jobs and a better life in Europe.

Attempts became scarcer when Spain stepped up patrols in the mid-2000s, but the route is seeing a fresh surge.

“New shipwreck off the coast of Nouadhibou #Mauritania of approximately 40 persons on board, there is one survivor (from Guinea),” the UNHCR special envoy, Vincent Cochetel, tweeted on the incident.

“UNHCR, along with authorities and partners, are trying to step up efforts to prevent such tragedies, but traffickers keep lying to their clients. The sunken boat was carrying migrants and refugees,” Cochetel said.

Nearly 2,800 illegal migrants arrived by boat in the Canary Islands between January 1 and July 14, Spanish Interior Ministry data show, five times as many as in the same period in 2019.

Late last year, at least 62 people drowned off the Mauritanian coast and around 80 had to swim for shore after the boat carrying them northwards from Gambia sank, one of the deadliest incidents along the route in recent years.