Twenty-one rescue operations have picked up more than 4500 people off the Libyan coast, according to the Italian coastguard, as calm seas sparked a flurry of attempts at the perilous Mediterranean boat crossing.
Among those taking part on Saturday was Doctors Without Borders ship Bourbon Argos, which told AFP it had rescued more than 800 people, who were expected to be brought to safety in Italy along with the rest of those saved.
"We started before first light this morning with our first rescue. We rescued two wooden fishing boats and two rubber dinghies," said Simon Burroughs, emergency coordinator for search-and-rescue missions by the medical group - commonly known by its French initials MSF.
Burroughs said those rescued included Eritreans, Nigerians, Somalis, Libyans, Syrians and west Africans.
The 21 operations took place between 30 and 40 nautical miles off the Libyan coast, and saw rescue workers pluck people from nine boats and 12 dinghies.
The body of a woman was also recovered.
The mass effort was carried out by an Italian military ship, the MSF's Bourbon Argos, the MAOS search and rescue Phoenix, a Croatian vessel operating under EU border agency Frontex, two vessels operating within the Eunavfor Med mission - one British, one German - and the Italian coastguard.
In videos sent to AFP by MSF, hundreds of people in brightly coloured clothes could be seen sprawled out on the Argos, a nearly 70-metre-long Luxembourg-flagged ship which typically carries around 700 people.
"It's quite a big boat, but at the moment every inch of deck space is covered. People are extremely relieved to be off of their sinking boats," Burroughs said.