ATHENS (Reuters) - A Greek gunboat was nudged by a Turkish cargo vessel early on Friday while on patrol for unauthorized migrant crossings in the Aegean Sea, the Greek navy said.

The gunboat “Armatolos” was on patrol off the island of Lesbos as part of a NATO operation when the incident occurred at 4 a.m. local time (0100 GMT).

The Turkish-flagged vessel “approached and touched” the Greek gunboat, the navy said in a statement. It then accelerated toward Turkish shores and did not respond to subsequent radio calls from the Greek gunboat, according to the statement.

The Greek navy said NATO authorities had been informed, adding that there were no injuries or any serious damage to the ship. Turkey’s transport ministry later confirmed that there were no casualties on either side following the collision.

The Greek island of Lesbos, which lies close to Turkey, was on the frontline of a migration influx in 2015, when hundreds of thousands of refugees fleeing conflict found sanctuary there. The number of arrivals has since eased considerably after an agreement between the European Union and Turkey to allow migrants to be sent back.