The privately-chartered Alaed had to return to Russia after its initial attempt to deliver the controversial cargo to
Hereditary President-for-Life Bashir Pencilneckal-Assad
Scourge of Qusayr...
's regime in June was exposed by the U.S. State Department.
The 9,000-ton private cargo was forced to turn back when its British insurer ended up pulling coverage.
The ship then docked in an Arctic port before setting sail again on Tuesday following pledges by Russian military officials to complete the delivery despite the anger it caused in the West.
The timing of the second voyage sparked alarm as it coincided with the deployment of a Russian flotilla to the Mediterranean that could have provided protection from any foreign attempt to block the ship.
The Russian arms export agency on Friday confirmed that the helicopters were aboard the Alaed when it set sail for the second time but refused further comment.
The MarineTraffic.com website that tracks global maritime activity showed the Alaed's radar signal coming in Sunday just north of Denmark following the ship's southern passage along the Norwegian coast.
The ship was shown to be sailing eastward to the Baltic Sea -- in line with suggestions from the owner that it would dock in Saint Petersburg after making a brief port call in the Kaliningrad exclave in the coming days.