Rescuers are searching for scores of migrants missing in the Mediterranean after their boat capsized off the south Italian island of Lampedusa.
Italian coast guards rescued 48 and three were saved by a fishing boat, but 20 deaths were confirmed and at least 130 people are unaccounted for.
Officials say the boat left two days ago from western Libya.
Lampedusa has struggled to cope with thousands of migrants arriving by boat from north Africa.
The Italian coast guard responded to a distress call from the boat, which was in Maltese waters some 70km (40 miles) from Lampedusa, at about 0400 local time (0200 GMT) on Wednesday.
Three coast guard vessels were dispatched along with at least one helicopter, which spotted the bodies in the water. A Maltese plane was reportedly also involved in the operation.
Lifejackets and lifeboats were cast into the water to help any survivors.
Coast guard spokesman Vittorio Alessandro told AFP news agency the boat, just 13m (42 ft) long, had been caught in high seas caused by strong winds and had overturned after passengers panicked.
Coast guards said the boat had been carrying around 200 people but the International Organisation of Migration (IOM) put the figure at 300.
Teams of rescuers, working in conjunction with the Maltese authorities, battled heavy seas, a force six storm and winds of up 30 knots (35 mph; 55 km/h) all day.
'Eritreans and Somalis'
The captain of the fishing boat described what he said was a terrifying scene.
"What we saw was incredible: heads were coming in and out [of the water] and people were screaming," Francesco Rifiorito told Italy's Ansa news agency.
"We did all we could."
Lampedusa's small field hospital has been overwhelmed, the survivors lying on beds around electric heaters to combat hypothermia.
The coast guard said the boat had left two days ago from the town of Zuwara in western Libya, which is embroiled in a civil war.
Those on the boat were mostly Eritreans and Somalis, they added. However, according to the IOM, the migrants and asylum-seekers came from Bangladesh, Chad, Ivory Coast, Nigeria, Somalia and Sudan.
Among them there were five children and 40 women - of whom only two survived, the organisation said.
The European parliament held a minute's silence to mark the tragedy.
Hundreds of refugees from Libya, many of them migrant workers, have landed in Italy in recent days.
Italy and Tunisia agreed measures on Tuesday to stop large numbers of illegal immigrants arriving on Lampedusa from Tunisia, which has also been in turmoil since a revolution in January.
Italy says it will give six-month residency papers to some 20,000 migrants already in Italy, but new arrivals will be deported.
The accord followed talks between Italy's Prime Minister Silvio Berlusconi and Tunisian ministers in Tunis on Monday. Mr Berlusconi also visited Lampedusa last week and pledged to tackle the island's migrant influx.
Italy has moved many migrants from Lampedusa to the mainland, because they outnumbered locals and overwhelmed the holding facility there. Unhygienic conditions, with dozens of migrants sleeping rough outdoors, created a health risk.