An unknown number of people are missing, presumed drowned
At least 588 people have been rescued from the Mediterranean in the last week.
The charity Médecins Sans Frontières (MSF) say they are now onboard the Aquarius - a search and rescue vessel it runs with SOS Méditerranée.
But it says an unknown number of people are missing, presumed drowned, after a day of rescues on Wednesday November 1st.
Dr Seif Khirfan is MSF's medical doctor on board the Aquarius.
"The situation suddenly turned into a nightmare when one of three rubber boats overloaded with men, women and young children collapsed and dozens of people fell into sea.
"Our teams launched all available floatation devices, distributed life jackets and pulled people from the water.
"We were able to revive a man in cardiac arrest who was then medically evacuated by helicopter to Italy.
"Although no bodies were recovered, we witnessed people submerged under the water."
The charity says with worsening winter conditions in the Mediterranean, there were multiple cases of mild to moderate hypothermia.
The medical team also treated older injuries people had suffered while inside Libya.
"One man had an open fracture and dislocation of his left ankle which was one month old.
"He told me he sustained the injury trying to escape gunfire in Libya", Dr Khirfan said.
"Another man had his arm broken a week earlier while arbitrarily detained in Libya."
The vast majority of people rescued in the Mediterranean by MSF have come through Libya.
"People do not undertake this journey lightly, people do not risk their own lives and the lives of their children if there are easier options available to them", said Luca Salerno, who leads MSF's teams onboard the Aquarius.
"The European Union and individual member states need to take urgent action to provide safe and legal channels for people to seek asylum, create legal migration pathways and make wider use of legal entry schemes so that desperate people are not forced to risk their lives on the Mediterranean."