Ukraine's security service announced on Monday that its underwater drones successfully struck a Russian submarine in the Black Sea port of Novorossiysk. This is the first time such an underwater drone attack has happened in the ongoing war with Russia. The Security Service of Ukraine (SBU) said on Telegram, "The Security Service of Ukraine carried out another unique special operation and launched a naval attack in the port of Novorossiysk." They added, "For the first time in history, Sub Sea Baby underwater drones blew up a Russian... submarine." The SBU reported the submarine was armed with four Kalibr cruise missile launchers that had been used against Ukraine. The damage was described as "critical," and the vessel was "effectively put out of action." Russia has not responded to these claims yet. Recently, Ukraine has stepped up naval attacks on Russian ships in the Black Sea. This comes amid Russian strikes on Ukraine's port of Odesa. Two Turkish cargo ships were also hit in recent days during what Ukraine said were attacks on Russian targets. Turkey reacted by calling for an end to attacks on ports and energy facilities to avoid worsening the situation in the region. Since Russia invaded Ukraine in February 2022, Ukraine has continuously used drones and missiles to target Russian naval forces in the Black Sea.