The EU along with over 40 countries urged Russia to withdraw troops from the Zaporizhzhia nuclear power plant.
Meanwhile, former UN chief Ban Ki-moon is visiting Ukraine to meet with President Zelenskyy and other officials.
Lee Shi-hoo has the latest.
The European Union and 42 countries around the world, including South Korea and the United States, issued a statement on Sunday urging Russia to withdraw its troops from the Zaporizhzhia Nuclear Power Plant.
The statement, published on the official website of the EU, read that Russia's control of the power plant "poses a great danger" to the principles of nuclear safety and security outlined by the International Atomic Energy Agency.
It called for Russia's withdrawal of its military forces and all other unauthorized personnel, so that the operator and the Ukrainian authorities can resume their responsibilities and the operating staff can conduct their duties without interference.
Meanwhile, during a televised video address on Monday,Ukrainian President Volodymyr Zelenskyy called on the world to introduce tough sanctions as a response to what he called Russia's "nuclear blackmail".
"And if now the world lacks the strength and determination to protect one nuclear plant, it means that the world is losing, losing to terrorists, yielding to nuclear blackmail."
He added that if a catastrophe occurs due to Russia's actions, the consequences could hit even those who remain silent.
According to a BBC report on Monday, Ukrainian forces have struck the headquarters of Russia's shadowy Wagner paramilitary group of mercenaries in Popasna in eastern Ukraine.
Serhiy Haidai, the governor of the Luhansk region, said the base's whereabouts were established "thanks to a Russian journalist".
Last week, pro-Russia correspondent Sergei Sreda posted a photo on Telegram of the base with its apparent address.
According to the BBC, quoting western experts, Wagner is a group of state-sponsored mercenaries who act in the Kremlin's interests.
Meanwhile, on Tuesday local time, former UN Secretary-General Ban Ki-moon is having a meeting with President Zelenskyy in Kyiv.
Ban will arrive with former President of Colombia Juan Manuel Santos, as a member of The Elders, a group of senior global leaders working for peace and human rights.
Ban will stay in Ukraine for around 12 hours during which he will also meet with Ukrainian officials and speak during a workshop hosted by the European Institute of Peace.
Lee Shi-hoo, Arirang News.