COPENHAGEN (Reuters) - A group of 27 migrants who had been stuck onboard the Maersk Etienne tanker for more than a month have been transferred safely to a ship operated by the NGO Mediterranea, Maersk Tankers said on Friday.

The tanker's crew rescued the migrants, including a pregnant woman, on Aug. 4 near Malta from a wooden dinghy that had been at sea for days and sank immediately after the rescue operation.

Neither the Maltese, Italian nor Libyan authorities had let them come ashore, according to Maersk Tankers, the operator of Maersk Etienne.

The migrants had been sleeping on mattresses and blankets, some on the deck protected from the sun by makeshift shades. Their physical and mental health had worsened in recent days, resulting in three of them jumping overboard on Sunday only to be rescued by the crew, Maersk said. 

Maersk Tankers had requested help from Mediterranea to conduct a health assessment of the migrants using the medical team onboard the Mare Jonio vessel.

"The transfer to the ship occurred following their assessment that the rescued persons' condition called for immediate care in suitable medical facilities," Maersk Tankers said in a statement.