"Those that were on deck would have managed to jump, some of them drowned and some of them were saved," said Martin Xuereb of the Migrant Offshore Aid Station in Malta.
Medecins Sans Frontieres (MSF) Dignity I vessel was one of the rescue boats.
"It was a horrific sight, people desperately clinging to lifebelts, boats and anything they could to fight for their lives," (MSF) project co-ordinator said.The rescued migrants have been taken to Italy where they will undergo normal entry procedures. 25 bodies has so far been recovered from the sea. The Mediterranean Sea is the world's most deadly border area for migrants.
Switzerland-based International Organization for Migration (IOM) said on Tuesday that more than 2,000 migrants have died so far this year trying to cross the sea to reach Europe, confirming this as the deadliest route for migrants in search of a better life.