Russian prosecutors found no suspicious materials on the ship Arctic Sea despite media reports it was carrying an air-defence system for Iran, Russian newswires reported on Saturday.

Russia's foreign minister denied the British and Russian press reports earlier this month.

The Maltese-registered cargo ship was officially carrying timber from Finland to Algeria when it was boarded on July 24 by eight men. They were charged with kidnapping and piracy after it was intercepted by Russian warships off Cape Verde.

Since then there has been speculation the ship, crewed by Russians, Estonians and Latvians, was carrying a secret cargo.

British and Russian press reports, citing military sources in Israel and Russia, said the Arctic Sea had been loaded with Russian S-300 missiles at the naval port of Kaliningrad without the Kremlin's knowledge.

Mossad, Israel's intelligence service, had been monitoring the shipment and tipped off Moscow.

A spokesman for the Russian Prosecutor General's Investigative Committee said prosecutors found nothing but timber on the ship, anchored near the Canary Islands.

"The ship was searched with the help of modern appliances, inside and outside. There was nothing but timber and lumber. Nothing that could compromise Russian Federation was found," Interfax news agency quoted him as saying.

However, suspicions persist in the media, with reports that officials from Spain, Malta and Russia couldn't agree on how and where to transfer the ship, while Spain denied it entry to its port of Las Palmas in the Canary Islands.

Last week Israeli Prime Minister Benjamin Netanyahu had visited Russia but his office declined to elaborate on the affair. - Reuters