More than 7,000 migrants may have perished at sea or while crossing deserts trying to reach a safe haven this year, believed to be the deadliest on record, the International Organisation for Migration (IOM) said on Tuesday.
In what it called the first global estimate based on data from border agencies and activist groups, the IOM said at least 2,360 migrants died in 2013 chasing the dream of a new life, many having paid smuggling gangs to make the perilous trip.
But that figure, drawn mainly from Western countries which keep and share their data, could be dwarfed by the numbers dying while heading from Africa to the Middle East.
Some 2,000-5,000 Africans are thought to have lost their lives while crossing the Sinai and the Gulf of Aden to reach Yemen, the gateway to rich Gulf Arab states, but no firm figures are available, the IOM said.
"We will never know the true total, as many migrants died anonymously in deserts, in oceans or other accidents," IOM director-general William Lacy Swing said in a statement ahead of International Migrants Day on Wednesday.
Even the conservative figure of 2,360 is higher than last year's newly established estimate of 2,109.
"We believe it is a record. It is more than last year and we think it is a great under-estimate. This isn't science, but it is a wake-up call to look at these numbers. They are tragic," IOM spokesman Leonard Doyle told Reuters.
Many fall victim to closed-door policies in rich countries whose tighter borders have contributed to a human smuggling trade estimated to be worth $35 billion a year, the IOM said.
In one the worst disasters of Europe's chronic immigration crisis, more than 360 mainly Eritrean migrants drown within sight of land while attempting to reach the Italian island of Lampedusa in October after their boat from North Africa caught fire and capsized,
An estimated 200 people went missing when a second boat sank a week later.
The flow of refugees and migrants trying to reach the European Union has also been fuelled by civil war in Syria and unrest in Egypt and other Arab and African countries.
"Why do people risk their lives and the lives of their families, over and over, every hour of every day when the best that awaits them is a frosty reception?," said Swing. "The answer is simple: Desperation".
Some 92 decomposing bodies were found strewn across the Sahara desert in northern Niger in October after their vehicles broke down and they died of thirst. Northern Niger lies on a major corridor for people-trafficking from sub-Saharan African into North Africa and across the Mediterranean into Europe.
Migrants have also died on perilous boat journeys from Indonesia to Australia and off the coast of Thailand, the IOM said. Christmas Island is a frequent destination for refugee boats from Indonesia and a favoured route for human smugglers.
"Migrants from Central America are raped, robbed, beaten and killed as they try to enter the USA from Mexico," IOM said.
Some 444 migrants have died this year in Pima County, Arizona, one of the most transited regions for irregular migrants entering the United States from Mexico, it said, extrapolating from U.S. data.
Thirty Haitian migrants are believed to have died when their overcrowded boat capsized off the Bahamas last month.
The paradox is that while one in seven people worldwide are migrants in one form or another, there has been a "harsh response to migration in the developed world", the IOM said.
Syria's war has driven at least 2.3 million refugees into neighbouring countries and North Africa in "the largest displacement crisis since the Rwanda genocide", according to U.N. refugee agency chief Antonio Guterres.
"There is something fundamentally wrong when a Syrian family with women and children that has fled this dramatic conflict in Syria, needs to take a boat with high risk of drowning, to get to Europe," he told a news conference on Monday.