Ukraine carried out a sea drone strike overnight on a Russian oil tanker in the Kerch Strait, a day after one of Moscow's ships was hit in the Black Sea, AFP reported on Saturday.

It was the latest attack around the Black Sea since Moscow exited the Black Sea grain deal despite the conflict between Ukraine and Russia.

The oil tanker's crew was safe, but the attack damaged the engine room, the Maritime Rescue and Coordination Center of Novorossiysk stated on Saturday. A group of rescuers and two tugboats went to the area to help the tanker.

The attack happened in the early hours of Saturday, making loud noises that alarmed the residents of Kerch, a city on the eastern tip of Crimea. The 19-kilometer-long Crimean Bridge, which links mainland Russia with Crimea, closed temporarily because of a threat of attack but reopened later.

A Ukrainian security source told AFP that the "successful special operation," which involved a naval drone and explosives, was carried out jointly by Ukrainian Security Service and Ukrainian navy on Ukrainian territorial waters.

The Russian oil tanker SIG was hit around 11:20 p.m. (2020 GMT) Friday south of the Kerch Strait, Russia's Federal Agency for Sea and Inland Water Transport said, adding that "the ship is afloat."

On Friday, Ukraine said it carried out a seaborne drone strike on the Olenegorsky Gornyak, a Russian warship, at the Novorossiysk naval base in southern Russia.

However, Russia's Defense Ministry said in its statement that "the armed forces of Ukraine attempted to attack the Novorossiysk naval base with two unmanned sea boats."

"In the course of repelling the attack, the unmanned boats were visually detected and destroyed by fire from the standard weapons of the Russian ships guarding the outer waters of the naval base."

It made no mention of any damage in its short statement.

(With input from agencies)