Ukrainian President Volodymyr Zelenskyy has met the head of the UN's nuclear watchdog following Russia's claim to a nuclear power plant in his country.

In the meeting with IAEA Director General Rafael Grossi in Kyiv, Zelenskyy accused the Russians of "nuclear blackmail." He said, "The main problem remains unresolved: the presence of soldiers at the nuclear plant. According to our information, which comes from the workers, there are around 500 Russians there. What do we do with this?"

Russian troops seized the Zaporizhzhia plant, Europe's biggest, in March.

The IAEA sent two inspectors there last month, where they have continued to assess safety. Its chief now says it is sending two more.

The IAEA director general said, "We are not changing our line. We are continuing saying what has to be done which is basically to avoid a nuclear accident at the plant which is still a very, very clear possibility."

Grossi also said that he hopes to discuss the plant when he travels soon to Moscow. He also stressed that the facility belongs to Ukraine, despite Russia's claim that it now owns the plant.

Russia is continuing missile attacks in the area. The Zaporizhzhia mayor said on Thursday that Russian troops shelled a residential complex, killing three people.

A close aide to Russian President Vladimir Putin says Moscow is now effectively at war with NATO nations.

Security Council Secretary Nikolai Patrushev pointed out that the risks of sabotage and terrorism have been rising in Russian-occupied areas. He accused Western nations of trying to expand what he called hostile actions into Russian territories.