ROME (Reuters) - A charity rescue ship recovered the bodies of 11 migrants off the coast of Libya on Friday after saving more than 160 people from boats close to the North African country, the Doctors Without Borders (MSF) group said.

MSF said its Geo Barents search and rescue vessel picked up 146 migrants in two operations and then found a further 20 in a separate boat. However, they also plucked the bodies of 11 people who were seen by a spotter plane floating in the sea.

"We do not know the precise cause of this tragedy, but we know that people continue to die in a desperate attempt to reach safety. This slaughter must end," MSF said on the social media platform X.

The Sea Watch group, whose plane saw the bodies, said they tried to contact Libya's coast guard to go and retrieve the dead, but received no reply. "This is what happens in the Mediterranean, even when nobody sees it," it said in a statement.

The United Nations has registered more than 20,000 deaths and disappearances in the central Mediterranean since 2014, making it the most dangerous migrant crossing in the world.

Italy has urged Tunisia and Libya to do more to stop would-be migrants from putting to sea. It has also clamped down on the operations of rescue ships, saying they encourage people to head to Europe - a charge the charities deny.

Underscoring the restrictions imposed on the rescue ships, Italy on Friday told Geo Barents to take its latest group of migrants to the northern port of Genova - more than 650 nautical miles from their position and far away from the much more convenient ports in nearby Sicily.

"This will significantly delay assistance for the ... survivors who endured a lot already," MSF said.

(Reporting by Crispian Balmer in Rome; Editing by Matthew Lewis)