Government spokesman Ali Rabiei did not identify who bought the 2.1 million barrels of crude oil estimated to be worth $130 million (€117 million).
He added that the buyer of the oil will now decide the ship's destination.
After being blocked from docking in Greece, the vessel had been headed to Turkey over the weekend, although it is not clear whether it will stop there.
The ship is still currently in the Mediterranean Sea and heading east.
US trying to seize tanker
The Adrian Darya 1, previously called Grace 1, was detained for weeks by the British Royal Marines off Gibraltar after authorities seized the vessel on suspicion of violating European Union sanctions with Syria.