MOSCOW (AP) — Russia's foreign minister rejected speculation that a hijacked Russian-crewed freighter was carrying S-300 missiles possibly destined for Iran.

Russia said the freighter Arctic Sea was seized by pirates in the Baltic Sea in late July after leaving a Finnish port.

Russian naval vessels intercepted the ship weeks later off Cape Verde, thousands of kilometres from the Algerian port where it was purportedly supposed to deliver a load of timber.

But an array of questions continue to cloud the incident.

Some observers have suggested that the seizure of a ship in the crowded Baltic, especially one carrying a comparatively low-value cargo, was unlikely as an act of straightforward piracy.

A Russian shipping expert and an EU anti-piracy official have speculated that the vessel was carrying a clandestine cargo, possibly S-300 surface-to-air missiles for Iran or Syria.

But Foreign Minister Sergey Lavrov said the rumours of S-300s on board the Arctic Sea were "completely untrue".

Separately, Russian President Dmitry Medvedev's spokeswoman, Nataliya Timakova, also dismissed the claims that the Arctic Sea was shipping missiles as "speculations," and said Russian investigators would provide answers to questions about its cargo once the ship arrives in the Russian Black Sea port of Novorossiisk.

Russia's top investigative body, the general prosecutor's Investigative Committee, said in a statement that it had already had made a "thorough" inspection of the ship's load of timber and found no unauthorised cargo.