Eleven people died and more than 60 were missing, including 26 children, following two migrant shipwrecks off Italy's southern shores, aid groups, coastguard officials and UN agencies said on Monday.
German aid group RESQSHIP, which operates the Nadir rescue boat, said it picked up 51 people from a sinking wooden boat, including two who were unconscious, and found 10 bodies trapped in the lower deck of the vessel.
Survivors were handed over to the Italian coastguard and taken ashore on Monday morning, while the Nadir was making its way to the Italian island of Lampedusa, towing the wooden boat with the deceased, the charity said.
The UN refugee agency UNHCR, the International Organisation for Migration and UN children's agency UNICEF said in a joint statement the boat had set off from Libya, carrying migrants from Syria, Egypt, Pakistan and Bangladesh.
The second shipwreck took place about 200 km (125 miles) east of the Italian region of Calabria, as a boat that had set off from Turkey caught fire and overturned, the agencies said.
They said 64 people were missing at sea, while 11 were rescued and taken ashore by the Italian coastguard, along with the body of a woman.
Shakilla Mohammadi, a staffer of the Doctors Without Borders (MSF), said she heard from survivors that 66 people were unaccounted for, including at least 26 children, some only a few months old.
"Entire families from Afghanistan are presumed dead. They left from Turkey eight days ago and had taken in water for three or four days. They told us they had no life vests and some vessels did not stop to help them," she said in a statement.
The UN agencies said migrants from the second shipwreck came from Iran, Syria and Iraq.
The incidents confirmed the central Mediterranean's reputation as one of the world's most dangerous migration routes. According to UN data, more than 23,500 migrants have died or gone missing in its waters since 2014.
UN agencies called on EU governments to step up Mediterranean search and rescue efforts and expand legal and safe migration channels, so that migrants "are not forced to risk their lives at sea".
Earlier this month 11 bodies were recovered from the sea off the coast of Libya, while last year another migrant boat that had set off from Turkey smashed into rocks just off the town of Cutro in Calabria, killing at least 94 people.
