Military relations between North Korea and Russia are intensifying, worrying South Korea. North Korea has sent 1,500 of its troops to Russia to participate in the fight against Ukraine and is preparing to send another 10,000 troops. South Korea summoned the Russian ambassador to express its displeasure over the development and requested that North Korea withdraw its troops. PTI, Seoul. South Korea on Monday demanded the immediate withdrawal of North Korean troops in Russia. At the same time, it summoned the Russian ambassador to protest the growing military cooperation between Pyongyang and Moscow. South Korea’s intelligence agency has confirmed that North Korea has sent 1,500 special operations forces to Russia to help Moscow in its war against Ukraine. Ten thousand soldiers being prepared Earlier, Ukrainian President Volodymyr Zelensky said that his government had received secret information that 10,000 North Korean soldiers were being prepared to join the Russian army. During a meeting with Russian Ambassador Georgy Zinoviev, Deputy Minister Foreign Minister Kim Hong-kyun said that South Korea will use all means to counter actions that threaten its national security interests together with the international community. Russia's position: Our cooperation is not against South Korea The Russian embassy quoted Zinoviev as saying that cooperation between Russia and North Korea is not against South Korea's security interests. Ukrainian drones attack Russian wine factories Russian officials said on Tuesday that Ukrainian drone strikes caused an explosion at an ethanol plant, while two other wine factories in Russia were also damaged. Tambov Governor Maxim Egorov said on the Telegram app that the explosion hit a biochemical plant in Russia's Tambov region, causing a brief fire. Egorov said there were no casualties in the attack.