The four remaining sailors from the Arctic Sea, the cargo ship at the centre of an international piracy mystery, returned to Russia late Monday, the RIA Novosti news agency reported.

"I am glad that I finally am on my homeland's soil," Captain Sergei Zaretsky was quoted by RIA Novosti as saying at the airport of Russia's northern port city of Archangelsk, where the four sailors were greeted with champagne.

Zaretsky also denied that his ship was carrying any secret cargo.

The four sailors are not regarded as suspects and Russian authorities have already finished questioning them about the ship's mysterious hijacking, Russia's investigative committee said in a statement last week.

The statement came a day after the Arctic Sea, a Maltese-flagged vessel with a Russian crew, was formally handed over to Malta and arrived in the main harbour of the small Mediterranean island nation.

In recent weeks the wives of the four remaining crewmen issued a series of emotional public statements urging the release of their husbands, who were left aboard to staff the ship while it was under the control of the Russian navy.

The Arctic Sea was allegedly hijacked in July by masked men posing as police near the coast of Sweden, then recaptured in August by Russian warships.

The boldness of the seizure and the huge international effort to recover the ship prompted speculation that it may have been carrying a secret cargo.

But Maltese inspectors said on Thursday that they had determined the ship to be free of radioactive materials or dangerous chemicals.

Moscow has also strongly denied reports that the ship may have been carrying advanced S-300 anti-aircraft missiles to Iran.

Eight suspects -- including Russians, Estonians and Latvians -- have been accused of hijacking the Arctic Sea and are now awaiting trial in Moscow on charges of piracy and kidnapping. They have maintained their innocence.