More than 20 people are feared to have drowned off Italy, the UN's refugee agency said Monday, as good weather prompted fresh attempts at the perilous Mediterranean crossing.
"Two shipwrecks off Lampedusa with 22 missing. Condolences to those who have lost family members at sea," Chiara Cardoletti, the UNHCR's representative for Italy, said on Twitter.
"Action is needed to stabilise the situation in countries of origin and transit, reducing the reasons that drive so many people to risk their lives at sea," she said.
The 36 survivors of the first shipwreck told the Italian coastguard that 19 people on board their boat had died after it partially capsized, a UNHCR press officer said.
Three other people were reported to have died in a second incident, Federico Fossi told AFP, warning however that the details were hazy.
The Italian coastguard was unavailable for comment and it was unclear when the disasters happened.
Survivors of the first shipwreck -- including six minors -- had been travelling on a seven-metre-long boat that sank in Italian waters, according to the Repubblica daily.
They were rescued by a fishing boat, it said.
Those saved hailed from Burkina Faso, Cameroon, Guinea, the Ivory Coast and Sudan, and had paid between 500 and 600 euros ($650) for the crossing, according to the Stampa daily.
After four days of poor conditions at sea, the number of boats attempting the crossing to the Italian island of Lampedusa rose again on Sunday.
By Monday, there were 1,094 people in Lampedusa's migrant reception centre, built to take just under 400 people.
Over 36,000 people have arrived by sea in Italy this year, compared to some 9,000 in the same period last year, according to the interior ministry.
The International Organization for Migration (IOM) has recorded 537 deaths or disappearances in the central Mediterranean -- the world's most dangerous crossing -- so far this year.