Updated - A total of 49 immigrants have been rescued and 20 bodies have been recovered so far in the Central Mediterranean as the search goes on for migrants missing after their boat, carrying 200 people capsized off Lampedusa.

The AFM confirmed this morning that the Malta Rescue Centre had been in contact with the boat, some two hours before the incident happened. At the time it was still proceedings towards Lampedusa.

The boat capsized some 40 miles southwest of Lempedusa.

Italian coastguard rescue vessels rescued 46 people. Another three people were rescued by an Italian fishing boat.

"We are still hoping. Our boats and helicopters have thrown all sorts of lifejackets and lifeboats to allow people to hold on," a coast guard official said.

Helicopter pilots quoted by Italian news agency ANSA said they had seen "dozens" of corpses in the area including those of small children.

"We hoped one of them would raise their arm. But no-one did," one said.

Shaken-looking survivors wrapped in thermal blankets were helped off a coast guard boat on Lampedusa, television images showed. Some, including a heavily pregnant woman, were immediately taken to hospital in ambulances.

"The bad weather started at about six pm yesterday... Our boat broke apart. We fell into the water. It was hell. There was water in my mouth but I managed to stay afloat," ANSA quoted a 29-year-old Cameroonian, Peter Ugo, as saying.

The Italian Coastguard said in a statement that the boat was 13 metres long and had departed two days ago from the town of Zuwarah in western Libya. The statement said the people on the boat were mostly Eritreans and Somalis and included women and children.

The Armed Forces of Malta said that just after midnight, a detention service employee at the Hal Far Open Centre was told by a migrant residing ther that a number of illegal immigrants were at sea.

He provided a satellite phone number.

His information was, within minutes, supported by another call from a Somali man in Malta.

The Malta Rescue Coordination Centre plotted the migrants' vessel some 40 nautical miles to the south of Lampedusa and 101 nautical miles southwest of Malta. RCC Malta contacted the vessel, which reported there were 200 people on board and that it was proceeding north.

RCC Malta informed the Italian Coast Guard in Rome and Nato headquarters in Naples and asked them about the availability of rescue assets. Rome reported that a fishing vessel, the Cartagine, was some 10 nautical miles from the migrants and it had been diverted to investigate.

Between 1.35 and 3 a.m., several attempts were made to re-establish contact with the migrants’ boat via satellite-phone, but to no avail. At 3.08 a.m., Rome informed Malta that the fishing vessel was proceeding to the illegal immigrants’ boat location, along with two Italian Coastguard vessels. A helicopter had also been authorised by NATO to perform an overfly of the area.

When contact was established with the illegal immigrants by Malta at 04.12 a.m., it was confirmed that the boat was still underway and in a position 32 nautical miles south of Lampedusa and 96 nautical miles southwest of Malta. Rome confirmed that an Italian Coast Guard patrol boat was in the area.

At 5.35 a.m. Rome informed Malta that Italian Coast Guard patrol boats had intercepted the immigrants’ vessel, which had stopped without fuel at 4.15 a.m. Given the sea conditions prevailing at the time in the area, a mid-sea transfer of the persons on board could not be performed.

At 6.28 a.m., Rome informed Malta that the vessel had capsized due to the weather, and six individuals had been rescued.

By 6.50 a.m., the Italian patrol boats had rescued 46 immigrants, and were returning to Lampedusa.

In the meantime, a Mayday was relayed by Malta to all ships, requesting those in the area to assist.

At 8.10 a.m., Rome informed Malta that the Italian fishing vessel Cartagine had rescued another three individuals.

THe UN High Commissioner for Refugees António Guterres and UNHCR Goodwill Ambassador Angelina Jolie expressed shock at the reported drownings.

Hundreds of African refugees from Libya -- many of them migrant workers stranded after the start of an uprising against Libyan leader Muammar Gaddafi and the beginnings of a civil war -- have landed in Italy in recent days.

More than 20,000 migrants fleeing continuing unrest in Tunisia have also arrived on Lampedusa, sparking a humanitarian emergency.

Migrants often travel in rickety and overcrowded fishing boats and there have already been smaller accidents at sea.