The Greek coastguard has intercepted a Sierra Leone-flagged cargo ship in the south-eastern Aegean Sea with about 20,000 Kalashnikov assault rifles on board, officials say.

The cargo ship, Nour M, was taken to the island of Rhodes, where its Turkish captain and seven crew members were arrested.

The coastguard said efforts to give a full account of the firearms and ammunition on board the cargo ship were continuing.

"The exact destination of the arms and ammunition has yet to be verified," the it said.

The state-run Athens News Agency reported that the vessel, which was intercepted near the island of Symi, had set sail from Ukraine and was destined for the Turkish port of Iskenderun.

The ship was also allegedly carrying a large quantity of explosives, ANA said.

It said the ports of Tartus in Syria and Tripoli in Libya had also been declared as destination ports to marine traffic authorities. The ship's captain had declared Iskenderun as the destination port.

The Nour M was also believed to have been used in the past for drug trafficking, ANA said.