Hundreds of migrants stranded on board the Aquarius rescue vessel in the Mediterranean will be transferred to Italian ships and taken to Spain, French charity SOS Mediterranee said Tuesday.

The 629 migrants, including pregnant women and scores of children, were saved by SOS Mediterranee on Saturday.

The Aquarius rescue vessel was however caught in a dramatic standoff over the weekend that saw Italy and Malta refuse to allow it to dock.

"Supplies will be received shortly from an Italian vessel onto #Aquarius. Plan from MRCC (the Maritime Rescue Coordination Centre) Rome is that rescued people will later be transferred on Italian ships before heading together to" the eastern Spanish port of Valencia, the charity said on Twitter.

The development comes a day after the new Spanish government headed by Socialist Prime Minister Pedro Sanchez offered to allow the Aquarius to dock in Valencia, insisting it was an "obligation" to do so.