Libya's navy has confirmed it rescued 87 Europe-bound migrants, including six women and a child, off the country's Mediterranean coast, following a video released by a German aid group about the disaster.

Friday's statement from the navy says the Libyan coast guards found a sinking rubber boat whose bottom had collapsed on Thursday, leaving most migrants in the water and hanging onto what was left of the boat and plastic barrels.

It says the migrants — Arab and African nationals — were handed over to Libyan police after receiving humanitarian and medical aid.

Earlier, German group Sea-Watch said its aircraft had filmed three rescue operations by Libyan coast guards on Thursday.

Humanitarian groups object to returning migrants to lawless Libya, citing reports of abuse, beatings and other inhuman treatment.