A new monitoring mission from the U.N. nuclear watchdog arrived on Saturday at the Russian-held Zaporizhzhia nuclear power plant in southeastern Ukraine, Russia's Rosatom company said, after weeks of delay caused by military activity around the site.

Radio Free Europe/Radio Liberty correspondent Rikard Jozwiak and Russian nuclear corporation Rosatom have reported a new rotation of International Atomic Energy Agency (IAEA) experts arriving at the Russian-occupied Zaporizhzhia Nuclear Power Plant (NPP),

International atomic monitors are for the first time traveling through Russian territory rather than Ukraine to reach Europe’s biggest nuclear-power plant, said three diplomats briefed on the matter — a blow to Kyiv’s desire to avoid international recognition of the Kremlin’s ownership claims.

Ukraine said on Sunday it condemned a "breach of territorial sovereignty" by employees of the U.N. nuclear watchdog who visited the Russia-held Zaporizhzhia nuclear power plant in Ukraine via Russian-occupied territory.

The UN's nuclear watchdog defended itself on Monday against criticism from the Ukrainian government following the recent rotation of agency experts at the Russian-occupied Zaporizhzhya Nuclear Power Plant.