The mine, weighing up to 500 kilograms (1100 pounds) and containing up to 50 kilograms (110 pounds) of TNT, was found drifting in the water Wednesday near a local navy hospital on the shore, said Valery Strelets, spokesman for the local branch of Ukraine's Emergencies Ministry.
The report came as the USS Forrest Sherman called at the port to conduct drills with the Ukrainian navy. The U.S. destroyer was about 500 meters (yards) from the mine when it was discovered, Strelets said.
He said the mine was secured to prevent it from floating and would be transported about a mile (2 kilometers) offshore to be destroyed. Nearby streets were cordoned off and all shipping was ordered halted, Strelets said.
The USS Forrest Sherman was in no danger, Lt. Brian Badura, spokesman for the Commander of U.S. Naval Forces Europe, Sixth Fleet, said by telephone.
In Ukraine 's Black Sea port was discovered a World War II mine as a U.S. Navy ship called for a visit.
The month of October was rich with rare astronomical phenomena.