The captain of a Portuguese cargo ship has been arrested after colliding with a Greek warship on Tuesday.
The Greek Ministry of Merchant Navy said that the Polish captain of the Maersk Launceston had been detained after being questioned by port authorities.
The suspect has been accused of "shipwreck caused by negligence".
The incident took place around 07:30 local time (06:30 CET) off the coast of Piraeus, a major port near Athens, the Hellenic Navy said in a statement.
Two crew members of the Greek warship were "slightly injured" in the collision and were transferred to the Naval Hospital of Athens.
A total of 27 people were on board the minesweeping vessel, NTHI Kallisto, which suffered extensive damage to the stern and water ingress, according to the Merchant Navy Ministry.
A rescue operation was immediately launched by the Coast Guard and the Navy, and the 70-metre long Kallisto could be seen listing to one side with severe damage.
The Ministry said the warship was towed from the Saronic Gulf to the naval base of Salamina, an island near Piraeus.
The authorities have also banned the "Maersk Launceston" from departing. The cargo ship had been sailing under the flag of Portugal with a crew of 22 and had been carrying containers.
The shipping company Maersk have described the collision as a "serious incident" and the ships' owner, J.T. Essberger, has reported that there were no injuries onboard.
"The vessel has activated its emergency response procedures and the crew has been participating in the rescue operation for the seafarers of the naval vessel," the company said on Twitter.
"Immediately after the incident, the appropriate authorities were notified. The exact cause of this incident is not always known".
Piraeus port authorities are continuing their investigation into the collision.