In the wake of attacks by Ukrainian sea drones on two Russian ships in the Black Sea within 24 hours, the Ukrainian State Hydrological Service has issued a coastal warning to shipping services using several Russian ports.
It issued a coastal warning naming the ports of Anapa, Novorossiysk, Gelendzhyk, Tuapse, Sochi and Taman as within a "War risk area."
A Russian naval ship sitting off Novorossiysk was struck by a sea drone early Friday, and then one of the country's biggest oil tankers was attacked by another of the unpiloted watercraft just before midnight, according to a Ukraine Security Service source.
A Ukrainian advantage: Kyiv's maritime drones are proving very difficult to defend against and can travel hundreds of miles to their target. In using them, Ukraine is opening up a new front — and may be trying to boost morale amid slow progress in its counteroffensive.
"With each new combat mission, Ukrainian combat UAVs and maritime drones become more accurate, operators more experienced, combat coordination more effective, and manufacturers get the opportunity to improve tactical and technical characteristics," Oleksiy Danilov, secretary of Ukraine's National Security and Defense Council, said on Twitter Saturday morning.
Danilov said August was particularly successful for Ukrainian "hunters."
"The next step is to expand the scale, range of combat operations, and the level and severity of Russian losses," he added.
The potential disruption to Russian shipping from sea drones was further demonstrated Saturday when the appointed governor of Russian-occupied Sevastopol issued a warning to maritime traffic that one had been spotted by the Russian navy.
"The Navy has detected a surface drone, which is currently continuing its movement. All necessary measures are being taken to destroy it," Mikhail Razvozhaev announced. Russia-backed officials limited maritime travel in some areas as a result.
More background: The Ukrainian maritime drone operations appear to have escalated since Russia pulled out of the Black Sea grain initiative last month.
On July 20, the Ukrainian defense ministry responded to Russia's move by saying "the Kremlin has turned the Black Sea into a danger zone, primarily for Russian ships and ships sailing in the Black Sea towards Russian seaports and Ukrainian seaports located on the territory of Ukraine temporarily occupied by Russia. Responsibility for all risks lies entirely with the Russian leadership."
Russia, meanwhile, has stepped up its air assault on Ukrainian ports and grain infrastructure, particularly in the city of Odesa.