ROME • Hundreds of migrants attempting the perilous journey across the Mediterranean are feared to have drowned after their overcrowded fishing boat capsized off Libya, Italy's coast guard said yesterday.

The boat had run into difficulty some 15 nautical miles off Libya and sent out a distress call, which was picked up by the coast guard in Catania in Sicily.

Two vessels - the Medecins Sans Frontieres (Doctors Without Borders) ship Dignity One and Irish patrol vessel Le Niamh - were dispatched to the scene immediately, but the boat capsized after the migrants all rushed to one side in anticipation of being rescued, the coast guard said.

Some 400 survivors were plucked from the water and a search for others is continuing, the coast guard said.

Ms Nawal Soufi, an Arabic- speaking Italian based in Sicily who is often contacted by migrants in distress, told Agence France-Presse she had received a call earlier yesterday about a boat in trouble with some 600 people on board.

"It is probably the same boat," coast guard spokesman Filippo Marini said, raising fears that hundreds of people may have disappeared below the waves.

Three other ships have been sent to the area to search for survivors.

More than 2,000 migrants and refugees have died so far this year in attempts to reach Europe by boat, compared with 3,279 deaths during the whole of last year, the International Organisation for Migration said on Tuesday.

In Britain, the BBC reported Deputy Prime Minister Nick Clegg as saying that the European Union should "review entirely the arrangements that are in place because we just cannot, on moral grounds, have such large numbers of people dying in such regular intervals in the Mediterranean".

AGENCE FRANCE-PRESSE, REUTERS