ROME - The Italian coastguard rescued almost 500 migrants crammed into five small inflatable boats off the Sicilian coast in the Mediterranean Sea after receiving distress calls overnight, the coastguard said on Thursday.

Coastguard spokesman Marco di Milla said the migrants, mostly from sub-Saharan Africa, included some pregnant women and several people in need of hospital treatment.

"They were in inflatable boats of a maximum of 10 meters long, which can carry about 10 people safely. Instead, these boats were carrying up to 100 people," di Milla told Reuters. He said the boats likely had started their journey in the North African state of Libya.

Most of the migrants were taken to Lampedusa, a tiny island south of Sicily that receives thousands of immigrants each year.

Improved spring weather conditions have increased the numbers trying to make the treacherous journey across the Mediterranean, but thousands have died due to shipwrecks, harsh conditions and a lack of food and water.

An estimated 1,500 migrants lost their lives in the Mediterranean in 2011, many of them trying to escape the turmoil caused by the Arab Spring uprisings in North Africa, according to Human Rights Watch. It estimated the death toll in 2012 at more than 300.