Greece's culture ministry says two Roman-era shipwrecks found in deep waters off the country's western coast disprove the accepted theory that ancient shipmasters stuck to coastal routes rather than risking the open sea.

A ministry statement says the two 2nd century AD wrecks were discovered earlier this month between 1.2 and 1.4 kilometers (0.7-0.9 miles) deep

Tuesday's statement said these are the deepest known ancient wrecks in the Mediterranean.

They were located during an investigation off the islands of Corfu and Paxoi, in waters where a Greek-Italian gas pipeline is to be sunk.

A Greek oceanographic vessel using side-scan radar and robot submarines took footage of scattered pottery, ballast stones and what could be remains of the wooden ships.

The team also raised samples of pottery and marble artifacts.