Several migrants were on Friday allowed to disembark the Open Arms rescue vessel that has been stranded in the Mediterranean Sea for two weeks, leaving 134 others on board.
Open Arms, a Spanish charity organisation, said on Twitter that three people and an escort were urgently evacuated on Thursday due to medical complications.
The activists said the remaining 134 migrants on board must be taken to land as soon as possible.
However, the vessel was carrying 160 migrants, although some of them were evacuated to Italy and Malta due to poor health.
The vessel remains stuck in international waters off the coast of Lampedusa, due to the stringent migration policy enforced by Italy and Malta in recent months.
Both countries have been closing their ports to rescue vessels unless other EU member states agree first to take in those on board.
The European Commission has announced that France, Germany, Luxembourg, Portugal, Romania and Spain have agreed to take in migrants from the Open Arms vessel.
European Commission spokeswoman Vanessa Mock, said, no solution has been found yet for the disembarkation of the migrants and the commission has received no request to coordinate the process.
She urged EU member states to agree on a long-term predictable solution to allow the quick and safe disembarkation of migrants attempting perilous Mediterranean Sea crossings to reach Europe.
In recent months, France and Germany have sought to win over other member states for a proposed mechanism to redistribute migrants.
