Ukrainian President Volodymyr Zelenskyy called for fresh sanctions against Russia’s nuclear sector amid concerns about shelling at the Zaporizhzhia nuclear power plant in southern Ukraine.

Zelenskyy, in an address late Monday, warned of a potential “catastrophe” that would threaten other countries in the region.

“If now the world does not show strength and decisiveness to defend one nuclear power station, it will mean that the world has lost,” Zelenskyy said.

Both Russia and Ukraine have accused the other side of firing weapons near the facility.

That continued Monday with a Russia-installed official in Enerhodar saying Ukrainian artillery strikes landed near the plant, while a Ukrainian official said it was actually Russian forces that shelled the area in an attempt to make it look like a Ukrainian attack.

Ukrainian Defense Minister Oleksii Reznikov told VOA’s Ukrainian Service that “it makes no sense for us” to shell the facility “because today we understand the full level of nuclear danger to humanity. We survived the Chernobyl tragedy in 1986. It is the Ukrainians who know what the Chernobyl tragedy was in the first place and how many people died later from the radiation.

“That’s why we are calling on everyone to intervene, and we ask not only the [International Atomic Energy Agency] but also the entire international community to intervene and influence in order for this not to become another cause of a nuclear disaster in Europe,” Reznikov said.

With the fear of a disaster, Reznikov said, “We are convinced that Russian units should not be concentrated there and that what is happening now is simply a provocation and a kind of game to test the ‘nuclear nerves’ of the world’s society as a whole.”

The United Nations said Secretary-General Antonio Guterres discussed the conditions for the safe operations of the plant in a phone call with Russian Defense Minister Sergey Shoigu.

Guterres spokesman Stephane Dujarric told reporters there exists the logistics and security capacity in Ukraine to support a visit by inspectors from the International Atomic Energy Agency to the plant, should both Russia and Ukraine agree.

Russian foreign ministry spokesperson Maria Zakharova said Russia would do “everything necessary” for IAEA personnel to visit the site. Russian state media later quoted Igor Vishnevetsky, deputy head of the foreign ministry’s nuclear proliferation and arms control department, saying it would be too dangerous for an IAEA mission to travel through Kyiv to reach the plant.

Ukraine’s military reported heavy shelling Monday by Russian forces, with at least three more Ukrainian civilians killed and another 20 wounded.

The three deaths and 13 of the injuries were recorded in the eastern Donetsk region, the scene of intense fighting for weeks, as Moscow’s forces targeted numerous towns and villages since Sunday and hit dozens of residential buildings.

Another seven people were wounded in Kharkiv, the country’s second-largest city, where Russia also shelled residential buildings and an area near a bus stop.

Russian President Vladimir Putin hailed Moscow’s forces fighting in Ukraine, saying at an arms show that they are “fulfilling all the tasks that were set, liberating the Donbas step by step.” The Donbas is Ukraine’s eastern industrialized region that includes the Luhansk and Donetsk provinces.

Some information for this report came from The Associated Press, Agence France-Presse and Reuters.