Moscow  - Military intelligence from NATO helped Russia track down the Arctic Sea freighter which went missing for some three weeks, Russia's ambassador to NATO Dmitri Rogozin said Thursday.

The help was made possible via new NATO Secretary-General Anders Fogh Rasmussen after the two met in Brussels on August 11, Rogozin told Echo Moskvy radio. NATO had subsequently supplied regular data.

One of the suspected hijackers of the vessel meanwhile was reported by TV Rossiya to have said during questioning in Moscow that that his group were "members of an environmental organisation", and that there had been "good" relations with the ship's Russian crew.

The captain and three crew members were meanwhile still on the vessel off Cape Verde, reported the Interfax news agency, citing the Russian Foreign Ministry.

Previously, the Defence Ministry had said that the entire 15-man crew had been flown back to the Russian capital on two Ilyushin Il-76 military planes, together with their eight alleged hijackers.

They were accompanied by investigators who have been trying to puzzle out the freighter's whereabouts between its initial contact with hijackers July 24 and its Monday rescue.

A member of the investigative team told Interfax that the crew would only be released when it had been proved that they were not involved in the hijacking.

A Russian seamen's union has appealed to the government in an open letter to allow the crew - all Russian citizens who have been held incommunicado since Monday - to contact their family members.

Hijackers apparently posing as drug enforcement officers, boarded the freighter in Swedish waters of the Baltic Sea on July 24. However, the crew reported that they left.

The Arctic Sea next had contact with the British Coast Guard on July 28 before largely dropping off the radar for more than two weeks.

The hijackers - who Russian officials say hail from Russia, Latvia and Estonia - apparently gained access to the freighter when they appeared alongside it in a rubber dinghy and appealed for help, which the crew granted.

The Russian Defence Ministry said Wednesday that the rubber dinghy used by the pirates to board the vessel had been confiscated, along with a quantity of arms and ammunition.

The Finnish-operated ship was officially listed to be carrying timber for Algeria. But European and Russian military experts believe that an illegal supply of arms might have been hidden in the cargo. (dpa)