It’s already been established that they were not under armed control.

President Medvedev instructed the minister to monitor the situation closely and brief him on the outcome of the inquiry.

Details of the incident are likely to be provided by the end of the day, Serdyukov said.

The story is also quite intriguing because of the unprecedented level of secrecy surrounding the search process itself.

“The fact is that it was not a criminal assault, it was not an act of piracy, and what exactly it was we don’t know,” says Mikhail Voitenko, the Editor-in-Chief of the Russian Maritime Bulletin.

“The whole story was of a great level of secrecy. If you remember the NATO announcements and those of the Malta maritime authorities – they were all the same: ‘The operation is under way, but we cannot say anything',” Voitenko added.

Nukes or drugs?

The “Arctic Sea” cargo ship was sailing under a Maltese flag and had a Russian crew of 15, but radio contact with the ship was lost on July 28 along the coast of Portugal.

It was to arrive in Algeria on August 4 with a load of Finnish timber worth $2 million. And the relatively low value of its cargo, along with all the mysterious sequence of events, prompted much speculation as to what, in fact, the ship might have been transporting.

“It’s possible that there was something put in the hold before it was loaded with the timber,” John Burnett of the Maritime and Underwater Security Consultants told RT. “I don’t want to get into speculating too much, but it could be anything from chemical, biological, nuclear weapon, …but it is unlikely to be drugs because it was going to Algeria, and you wouldn’t take drugs to Algeria, you take drugs to Europe.”

Some go as far as to suggest that the whole operation was nothing but a Russian military exercise.

If that is the case, “it would be the only other reason that the Russian government would send its Black Sea fleet in a desperate search for this vessel,” John Burnett says.

“It’s either a training exercise, which I doubt seriously, or they were looking for this vessel because intelligence gave them an indication that there is something very dangerous aboard this ship,” Burnett concluded.

There were reports that the vessel was assaulted by armed men near Sweden, just days before its disappearance.

Russian and NATO fleets and satellite took part in the operation to locate the “Arctic Sea”.