The ship, the Alaed, which has emerged as something of a barometer of Russia’s intentions toward the government of President Bashar al-Assad, was reported heading south off Norway’s northern coast as of Thursday.

That location put the vessel close to a flotilla of four Russian naval vessels bound for the eastern Mediterranean Sea off the coast of Syria, as part of a Russian naval buildup in the area announced earlier this week, ostensibly for training exercises.

MarineTraffic.com, an Internet database that chronicles commercial shipping based on transponder signals required by the International Maritime Organization, registered the ship’s presence off the Norwegian coast on Thursday, though it had passed out of the range of the transponders in the North Atlantic by later in the day.

The Alaed’s reappearance on the open seas was first reported Thursday by the Barents Observer, a periodical published from the town of Kirkenes, near the northernmost point in Norway. Ships from Russia round the Scandinavian Peninsula near there, before heading south.

Embarrassingly last month for Russia, the Alaed, then Curaçao-flagged, was forced to scrub its voyage when its British insurer canceled coverage. That came a few days after Ms. Clinton announced the Russians were sending attack helicopters to Syria, despite assurances by authorities in Moscow that they sold no weapons to Mr. Assad that would be useful in his government’s repression of the uprising against him.

Russia countered that the helicopters were not new but were refurbished models owned by Syria that had required servicing under a longstanding contract, so their return to Syria violated no United Nations sanctions. But Russia turned the ship around anyway.

The vessel docked in Murmansk on June 24 and was reflagged as a Russian vessel, presumably bypassing the insurance problem.

It was reported en route again weeks ago by Russian news agencies, though apparently incorrectly.

The Barents Observer, citing an online link to the ship’s own transponder, reported the Alaed was sailing in a commercial shipping lane heading west and then south near Norway.

The publication quoted a Norwegian maritime official saying the Alaed was heading in the same direction as the military vessels. Their positions are not reported to the civilian tracking system but were believed to be 50 to 100 nautical miles away from the Alaed.

Earlier this week, Russian officials had hinted at a role for the naval flotilla in safeguarding ships, though the rebuff to Ms. Clinton’s efforts to halt the Alaed was unclear until its position near Norway, near the warships, became public.

RIA Novosti, the Russian news agency, cited Vyacheslav Dzirkaln, the director of a military aide agency in the Russian government, as saying the fleet would “be sent on a task to guarantee the safety of our ships, to prevent anyone from interfering with them in the event of a blockade.”

The owner of the Alaed, the Femco shipping company, issued a statement on Wednesday making clear that the helicopters and air defense weapons were still aboard. The company presented the statement in the context of an analysis of the legality of sending such weaponry on a commercial vessel.