Exactly 36 years after the meltdown in Chernobyl, conflict has rekindled concerns about the safety of nuclear sites in Ukraine. Russian troops are still occupying another of Ukraine's nuclear power plants.

The head of the International Atomic Energy Agency (IAEA), the UN atomic watchdog, Rafael Grossi visited the site of Chernobyl nuclear disaster in Ukraine on Tuesday and said the radiation levels there were now back to "normal" for the area.

"The radiation level, I would say, is at normal. There have been some moments when the levels have gone up because of the movement of the heavy equipment that Russian forces were bringing here and when they left," Grossi told reporters.

The head of IAEA said his agency was monitoring the situation daily.

Speaking near the sarcophagus that covers the nuclear reactor's radioactive remains, Grossi said the takeover by Russian forces had been "absolutely abnormal and very, very dangerous." Invading Russian forces controlled the Chernobyl exclusion zone for more than a month before retreating in late March. The occupation raised global fears of nuclear leaks.

Ukraine alleges that Russian soldiers moved heavy military equipment and dug trenches in highly radioactive locations during their occupation of the exclusion zone.

EU: Russian invasion 'jeopardizes nuclear safety'

On the anniversary of the 1986 Chernobyl accident, the EU reiterated its utmost concern over the nuclear safety and security risks caused by Russia’s recent actions at the Chernobyl site.

"Today, Russia's illegal and unjustified aggression in Ukraine again jeopardizes nuclear safety on our continent," the European Commission said in a statement on Tuesday. It said Moscow's forces had "targeted and occupied Ukrainian nuclear sites, recklessly damaging the facilities."

The EU also called on Russia to return control of the occupied Zaporizhzhia nuclear power plant to the Ukrainian authorities and "refrain from any further actions targeting nuclear installations."

Meanwhile, German politician Jürgen Trittin of the Greens focused instead on nuclear energy, saying: "Chernobyl was the beginning of the end of atomic energy. The shutdown, which Germany will finally complete this year, is still taking too long worldwide." Given the recent controversies over German energy policy surrounding the war in Ukraine, Trittin's comments might not meet unified agreement among allies.

Cruise missiles over a nuclear power plant

Russian troops seized the Zaporizhzhia atomic plant, Europe's largest, on March 3; it remains under Russian control.

Ukraine's state-run atomic energy company Energoatom said Russian cruise missiles had flown over the Zaporizhzhia nuclear power plant on Tuesday during an air strike on Zaporizhzhia.

"Missiles flying at a low altitude directly over the site of the Zaporizhzhia nuclear power plant, where there are 7 nuclear facilities with a huge amount of nuclear material, poses huge risks," Petro Kotin, Energoatom's acting chief, said in a statement on the Telegram.

"Thirty-six years after the Chernobyl tragedy, Russia exposes the whole world to the danger of a repeat of the nuclear catastrophe!" Kotin said.