Hundreds of Syrian refugees have been rescued in rough seas and brought to Italy's southern coast in the last 24 hours, the Italian coastguard said on Saturday.

Three boats carrying 809 refugees and possibly some migrants, including many women and children, were intercepted off the Mediterranean islands of Lampedusa and Sicily and off the mainland region of Calabria in the toe of Italy.

One boat carrying 171 refugees was in difficulty and gradually sinking when it was rescued about 25 miles (40 km) off Calabria, the coastguard said.

All the 359 refugees rescued off Syracuse in Sicily and the 171 rescued off Calabria appeared to be from Syria, the Italian authorities said, while the nationality of those rescued off Lampedusa was not available.

The number of Syrian refugees reaching Italy has increased steadily in recent months and the United Nations estimates that 3,300 have arrived since the start of August.

More than 2 million refugees have now fled Syria's civil war, mainly to neighbouring Iraq, Jordan, Turkey and Lebanon, out of a population of about 20 million. The two-and-a-half-year conflict is estimated to have killed more than 100,000 people.

Thousands of migrants and refugees try to reach Italy's southern shores in summer, when Mediterranean waters are calm enough for smaller boats to make the crossing, usually from Libya or Tunisia.

Though most come from sub-Saharan Africa, this year many are fleeing the Syrian civil war or political turmoil in Egypt and other parts of North Africa.

Many are drawn by hopes of finding work in Europe and often do not remain in Italy.

Illegal migrants intercepted by Italian authorities are taken to state-run immigration centres. Some leave the often lightly guarded buildings to seek work, and those who remain and cannot prove that they are political refugees can be sent home. - Reuters