The medical charity Médecins Sans Frontières (MSF) says it has been forced to terminate its search and rescue operations in the Mediterranean.
It says a sustained campaign of obstruction by the Italian government brought about the decision to withdraw its rescue vessel Aquarius.
It says Italy has twice stripped the ship of its registration, and falsely accused it of criminal activities.
Over 2,000 migrants have died trying to cross the Mediterranean this year.
Tom De Kok who is on board the Aquarius says forcing the MSF vessel out of the region will mean more lives are lost.
"Our work does save lives so if you ask me 'will our absence result in deaths?' the answer is unequivocally yes," said Mr De Kok.
Sustained attacks on search and rescue by European states will mean more deaths at sea, and more needless deaths that will go unwitnessed. https://t.co/JxX7hiigcm— MSF Sea (@MSF_Sea) December 6, 2018
MSF says the European Union is working to force migrants back to Libya - in contravention of international law.
"This has become a systematic delegitimisation of search and rescue activities," said Mr De Kok.
"The European Union Council agreement in June of this year said it would stand by Italy."