It is of “paramount importance” that the International Atomic Energy Agency be allowed to send experts to the Chernobyl nuclear power station, the agency has said, adding it is aware of recent drone footage reported to show trenches made by Russian troops in a contaminated area near the facility.

The IAEA said on Thursday it was still not able to confirm reports last week of Russian forces receiving high doses of radiation while being in the Chernobyl exclusion zone set up after the 1986 accident.

It said it is ready to visit the site as soon as it is possible to assess the radiation situation and provide other safety assistance. The agency said it must take “urgent action to help Ukraine in ensuring nuclear safety and security there”.

“I’m in close consultations with our Ukrainian counterparts to organise such a visit as soon as it is possible,” IAEA director-general Mariano Grossi said.