At least nine migrants drowned and 10 others, including four children, were missing after a tense series of rescues on Saturday in the Mediterranean that saved over 1,000 people, rescuers said.

Survivors saved by medical charity Doctors Without Borders (MSF) from a sinking rubber boat before dawn said six adults and four children were missing.

As the rescuers took 120 people to safety, there were fears that more may be missing at sea, an MSF spokeswoman said.

Nine bodies were found later in the day on another vessel, though their cause of death was unclear.

Along with the bodies of five migrants who died on Friday, they were transferred to the Norwegian Siem Pilot rescue ship, part of the Frontex European border security agency's mission in the Mediterranean.

The Italian coast guard, which coordinates rescues in the area, said at least 1,000 migrants had been saved on Saturday, adding that the number may rise.