The group, known by its French acronym MSF, says in a Tweet that the people, including 21 women and children, disembarked in the western coastal city of Khoms early Thursday. MSF provided water, food, blankets and hygiene kits to the group, which also included a pregnant woman and 6-month-old baby.
Libyan Coast Guard Spokesman Brig. Gen. Ayoub Gassim confirmed a boat carrying mainly Africans was rescued in the Mediterranean Sea, but rejected the term "forcibly returned," saying the Libyans "rescued them from the sea ... for their safety."
Libya is a major transit point to Europe for those fleeing poverty and civil war elsewhere in Africa. Traffickers have exploited Libya's chaos following the country's 2011 uprising.
Greek authorities say they have rescued 21 migrants found adrift in a small boat in a section of the northeastern Aegean Sea off the usual illegal immigration route.
The migrants were located Thursday between the island of Samothraki and the northeastern port of Alexandroupoli, after Greek authorities received an emergency call reporting their boat was in trouble.
Most migrants entering Greece illegally by sea from Turkey prefer the much shorter crossing to the eastern Aegean Sea islands, and the longer, northern route is rarely used.
Also Thursday, police in the northeastern region of Thrace said they detained nine Syrian and Afghan migrants found squashed into a car that was being driven west after crossing the land border from Turkey.
The driver, a 20-year-old Syrian, was arrested on suspicion of people-smuggling.