Sevastopol Governor, Mikhail Razvozhayev, said Saturday that Russia's Black Sea Fleet’s headquarters was attacked by a drone Saturday with no casualties reported.

"I am at the [Black Sea] Fleet’s headquarters now. A drone hit the roof here 25 minutes ago. Unfortunately, it was not downed. <…> There are no casualties," Razvozhayev wrote on his Telegram channel.

In a similar attack, a drone-borne explosive device detonated on July 31 at the same headquarters, leaving six people injured, according to officials.

It is noteworthy that Russia and Ukraine signed the United Nations-brokered Black Sea Initiative on grain and fertilizer exports on July 22.

Grain and fertilizer would be exported from the Ukrainian Black Sea ports of Odessa, Chornomorsk, and Yuzhny under the agreement, and cargo carriers would be guided into international waters by Ukrainian vessels to avoid mined areas. Then the vessels would proceed toward the Bosphorus Strait along an established corridor.

The parties also established the Joint Coordination Center (JCC) in Istanbul on July 27, which includes representatives from Russia, Ukraine, Turkey, and the United Nations. The JCC monitors the implementation of the Black Sea Initiative and inspects cargo ships to ensure that no unauthorized goods or personnel are aboard.

Read more: JCC authorized 12 ships to depart Ukraine: Official

US cancels ‘essential’ Black Sea drills over war in Ukraine

In the same context, US officials, who chose to remain anonymous, had told Newsweek that the US Navy canceled the "essential" Sea Breeze 2022 exercise in the Black Sea due to the war in Ukraine. 

The report pointed out that last year, the exercise was dubbed "essential" to preventing Russia’s alleged aggression.

In 2021, Sea Breeze involved 32 warships from NATO and partners, the report mentioned. 

Instead of the canceled maneuvers, NATO is conducting a smaller exercise, Breeze 2022, off the coast of Bulgaria between August 17-21, the report noted.

Breeze 2022 features a total of 24 warships, five aircraft, and two helicopters from ten nations. No US ships are participating in the drill.

Around 20 US mercenaries killed in Kharkov: Russian MoD

In another context, the Russian Defense Ministry confirmed on Saturday that the Russian air force has eliminated around 20 US mercenaries in Kharkov region by a high-precision strike.

"Over 100 militants, including up to 20 US mercenaries, have been killed in the area of ​[the village of] Andriivka, Kharkov region, as a result of a Russian air force strike against combat positions of the Kraken nationalist formation and a unit of foreign mercenaries," the ministry told reporters.

Read more: Over 40 foreign mercenaries killed in Donbass: Russia Defense Ministry