ROME (AFP) - The Italian navy said on Friday it had rescued in 24 hours more than 1,000 migrants attempting the perilous journey across the Mediterranean by boat in rough winter seas.

Some 823 migrants were picked up on Thursday and another 233 were rescued Wednesday as part of a major ongoing search and rescue operation to save the lives of thousands of immigrants heading for Europe in overcrowded and rickety boats, the navy said.

The immigrants, including 30 women and 42 minors, mainly hail from Egypt, Iraq, Pakistan and Tunisia.

Six military vessels and several helicopters were involved in picking them up and transferring them to the coastal town of Augusta in Sicily.

Immigration charities estimate that between 17,000 and 20,000 migrants have died at sea trying to reach Europe over the past 20 years, often crossing on rickety fishing boats or rubber dinghies.

The immigrants were rescued as part of the Italian government's "Mare Nostrum" operation, which mobilises warships, amphibious vessels and aircraft to try and prevent further tragedies like the two shipwrecks in October in which more than 400 immigrants died.