The Libyan Red Crescent has said that a patrol boat has recovered 17 bodies and rescued seven people during an operation to assist a stranded vessel off the North African country.

With Italy around 300 kilometres away, Libya has become a key launchpad for tens of thousands of migrants who risk their lives at sea trying to reach Europe each year.

The organisation shared photos on its Facebook page showing aid workers hauling black body bags from a boat.

It said the rescue operation was "one of the most arduous field missions to date."

The Red Crescent did not give information about the nationalities of those killed or those rescued, but said it provided humanitarian assistance to survivors along with the United Nations High Commissioner for Refugees.

"After eight days of distress, the Almarqab patrol boat, attached to the naval base, successfully rescued a stranded vessel. The operation resulted in the rescue of seven survivors and the recovery of 17 bodies," the Red Crescent said in a statement.

The Red Crescent, navy personnel, the coastguard and coastal security units mobilised for the rescue, which involved "over eight-hour operation of continuous work conducted under challenging conditions," it added.