ATHENS (AP) — Greek authorities say a Turkish cargo ship and a Greek warship have collided in the eastern Aegean Sea, without causing injuries or severe damage.

A Greek navy statement says the Turkish-flagged Karmate put on speed and made off into Turkish waters after Friday’s pre-dawn incident, ignoring radio messages from the Armatolos gunboat to stop, according to the Associated Press.

The navy said the collision in Greek waters southeast of the island of Lesbos was caused by the Turkish ship breaching international shipping safety rules.

Thr 180-foot (55-meter) Armatolos was taking part in a NATO operation to stop migrant-smuggling, the navy said.

The incident comes amid heightened tension between Greece and Turkey over Aegean territorial rights.

After striking the Greek gunboat, the “Karmate” increased speed and sailed toward the nearest Turkish shore, ignoring attempts by the “Armatolos” to hail it on the radio, Athens Macedonian News Agency says.

National Defence Minister Panos Kammenos has informed Prime Minister Alexis Tsipras and Foreign Minister Nikos Kotzias about the incident, as well as main opposition New Democracy.

Coast guard authorities and NATO authorities have also been alerted to the incident, which took place during a planned patrol by the “Armatolos” during the NATO operation “Aegean Activity” to combat migration flows in the Aegean.