Russia said on Tuesday it had arrested eight men for hijacking the Arctic Sea ship whose disappearance in July sparked an international sea hunt.

The two Russians, four Estonians and two Latvians were detained at sea after the Russian navy took control of the ship at an undisclosed location believed to be off the west coast of Africa.

"These people, claiming their boat had engine problems, boarded the Arctic Sea and, using the threat of arms, demanded that the crew follow all of their orders unconditionally," Defence Minister Anatoly Serdyukov said.

The Arctic Sea saga started after the cargo ship left a port in Finland on 23 July and disappeared from radars shortly after, sparking a massive naval hunt.

But even with the arrests important questions remain over what happened to the vessel. A respected Russian shipping expert, Mikhail Voitenko, said he believed important aspects of the story were being covered up.

Serdyukov said the Arctic Sea was hijacked in Swedish territorial waters in the Baltic Sea and added that the operation to rescue the crew was accomplished without a shot being fired.

"Eight people — not members of the crew — have been detained," he added, in remarks to President Dmitry Medvedev reported by Russian news agencies.

The crew of the Maltese-flagged, Russian-owned ship set a course for Africa and turned off all navigational and tracking equipment under orders from the pirates, Serdyukov said.

An investigation was underway aboard the Russian warship Ladny, where the 15 crew members and suspected pirates were being questioned, the reports quoted Serdyukov as saying.

He said the operation to "liberate" the 3988-ton ship came after coordinated action between Russian naval and air force units, but did not elaborate.

Arrangements were being made to repatriate the Russian crew, he added.

Officials in Praia, the capital of the Cape Verde archipelago, said that a Russian transport plane was on standby on the island of Sal waiting for the Ladny to put into port with the crew and fly them back to Russia.

Serdyukov first announced on Monday that the Arctic Sea had been found 300 kilometres off Cape Verde and its crew taken aboard the Ladny, an anti-submarine warfare vessel involved in the search.

There was still no word on the exact current whereabouts of the Arctic Sea itself.

Medvedev on Monday called for a full investigation of the Arctic Sea mystery and vowed that "all interested parties" would be informed on the results.

The official story is that the Arctic Sea was sailing from Finland to Algeria with a crew of 15 and a cargo of sawn timber estimated to be worth €1.16 million ($1.64-million).

Speaking at a Moscow news conference, Voitenko, editor of the online Sovfrakht Maritime Bulletin and an experienced seaman, listed five reasons why the official version was suspicious.

These included the delay in initial reports the ship had been attacked and the lack of distress signals despite sophisticated communications equipment aboard the vessel and crew mobile phones that would have been in signal range.

"This story is incomprehensible if you try to explain it as a criminal attack or a dispute between business competitors," Voitenko said.

"It makes sense only if looked at as a conflict between states... I believe states, state interests, were involved in what happened.

"I believe the countries involved found a solution and agreed to 'keep it in the family' without having the time to find a plausible explanation" for the mysterious voyage, Voitenko said.

Officials in Latvia and Estonia meanwhile said they had received no further information following Serdyukov's assertion that citizens from the two Baltic states took part in the attack on the Arctic Sea and had been detained.

And a NATO spokesperson in Brussels, Carmen Romero, again refused to be drawn out on how the alliance assisted Russia in finding the ship, saying only that it "closely monitored" the situation and remained in contact with Moscow.

AFP

It's JZ, leave a message... "Hi, this is Zuma. You know what to do. No, no... not the machine gun. Leave a message..."

Finding love in Zululand Susan Pletts ventures into Zululand and discovers that SA's hidden treasures are its people.

Visit our politics page Need the latest political news, features, interviews and profiles? Visit our dedicated page...