Aerial images of migrants aboard Aquarius rescue vessel in Mediterranean

Aid group SOS Mediterranee says it is transferring some of the 629 migrants rescued at sea onto other vessels for the voyage to Spain where the prime minister has offered safe harbour.

The Aquarius, the rescue ship operated by SOS Mediterranee, has been stuck at 35 nautical miles off the coast of Sicily since Saturday after Italy and Malta refused to accept the 629 passengers on board the ship.

SOS Mediterranee spokeswoman Mathilde Auvillain said Tuesday that some passengers were being transferred before the journey "for security reasons" because of deteriorating weather conditions.