The deaths brought to nine the number of destitute travelers who have perished in a week in the latest wave of migrants seeking a better life in Europe,
The four dead men were found on a fishing boat carrying 26 other migrants, which police escorted to a port on the Canary Island of Tenerife late Thursday, said spokesman Anibal Carillo, the AP reports.
Three other boats carrying a total of 270 migrants were also intercepted by police over the past 24 hours, said Carillo.
Thousands of migrants attempt to reach Spain's Canary Island archipelago in the Atlantic each year, an increasing number of them setting off in boats from Mauritania and Moroccan-controlled Western Sahara. Many die during the long and dangerous crossings.
Of those who get across, most are intercepted and taken to holding centers. Authorities then have 40 days to send them home or release them.
Immigrants who can be identified from official identity documents are sent back to their countries of origin or to the country from which they set sail if Spain has a repatriation agreement with it.
The Spanish government says more than 11,000 Africans from some of the continent's poorest countries have made the perilous trip to the Canary Islands from western coasts so far this year, already doubling the total for all of 2005. More than 1,000 are reported to have died attempting the voyage since late last year.