In a separate operation, two women found swimming at sea told rescuers that 128 other people had died in their wreck.
"I am deeply saddened by another tragedy on the high seas," said UN High commissioner for Refugees filippo Grand.
"So many lives could be saved through more resettlement and legal pathways to protection. The Mediterranean is a deadly stretch of sea for refugees and migrants, yet they still see no other option but to risk their lives to cross it.