Ukraine’s nuclear regulator has suspended a number of operating licenses at Chernobyl saying that the Russian troop occupation of the site has made the continuation of some activities there unsafe, the regulator said on its website last week.

Regulators said that destroyed bridges and roads meant that there were “no conditions for safe operation in the exclusion zone,” adding that many staff members could no longer safely access their work posts.

The damage by Russian troops, who moved on the site on February 24, had also interrupted supply avenues for the delivery of equipment, spare parts and other materials necessary for the safe operation at the sprawling former nuclear station.

It added that there had also been “the destruction, disabling and theft of computer, office and server equipment, databases and measuring equipment.”

Valeriy Seyda, the acting director of the Chernobyl site, blasted the regulator’s decision on the facility’s website, calling the license suspensions  “negligent” and a “deliberate sabotage. He added that his staff had manged to keep the site safe and “maintained full control over the nuclear facilities, nuclear material and radioactive waste” even during the period of the Russian occupation.

Russian forces had been in control of the Chernobyl plant for five weeks before withdrawing on March 31, their heavy armored vehicles churning up radiation in some of the plant territory’s most irradiated territories.

According to Chernobyl plant workers – hundreds of whom worked grueling shifts at gunpoint during the siege – Russian troops had taken up positions throughout the exclusion zone, a 2,600 square kilometer area around the plant that has been uninhabited since shortly after the Unit Four reactor exploded on April 26, 1986.

The site of the world’s worst nuclear disaster was finally decommissioned in 2000 when the last of its three still-operational reactors was shut down. Since then, the site has housed over 20,000 spent nuclear fuel assemblies stored in cooling pools, as well as the infrastructure for containing the radioactive remains of the ruined forth unit.

Ukraine’s national nuclear operator, Energoatom, reported that Russian troops had dug trenches in irradiated ground and that numerous Russian soldiers had suffered radiation sickness as a result – though that hasn’t been independently confirmed.

Five weeks following the Russian withdrawal, Rafael Grossi, head of the International Atomic Energy Agency, stressed that the Chernobyl site was still struggling to get its bearings.

Grossi said that the license suspensions “demonstrate that there is still much to do to restore Chernobyl to normal operation.”

Last week, Grossi met in Vienna with Oleh Korikov, head of Ukraine’s regulatory body. The two had met earlier at Chernobyl itself when the IAEA delivered safety-related equipment, conducted radiological measurements and restored transmission of safeguards data.