The Chernobyl nuclear plant has been cut from the country’s power network, Ukrainian officials have said.
According to nuclear power operator, Energoatom, officials are unable to monitor the radiation levels at the facility after power was severed on Wednesday.
With Russian soldiers now in full control of the facility, Ukrainian officials are also unable to repair connections and restore power to the plant.
Ukraine’s state energy operator, Ukrenergo, said in a statement: “The ongoing fighting makes it impossible to repair and restore power.”
Approximately 20,000 exhausted fuel assemblies are also stored at the facility and need constant cooling, Energoatom added.
Without cooling, temperatures in the pools will increase and risk releasing radioactive material into the environment.
Safeguard monitoring systems at the Chernobyl nuclear facility have also been “lost”, the head of the international nuclear energy watchdog said prior to the incident.
Russian forces seized the plant after invading Ukraine almost two weeks ago and have not allowed the 210 technical staff at the site to leave, the International Atomic Energy Agency (IAEA) said.
In a statement, IAEA added: “The Director General has indicated that remote data transmission from safeguards monitoring systems installed at the Chernobyl NPP had been lost.
“The Agency is looking into the status of safeguards monitoring systems in other locations in Ukraine and will provide further information soon.”
The safeguards refer to measures aimed at tracking nuclear material and waste products generated by the plant.
The IAEA has also warned staff at the facility have been held hostage and have not been allowed to leave since Russian forces surrounded and seized the plant on February 24.
Although the nuclear plant was decommissioned following the 1986 disaster, some 500 staff usually work there in order to monitor the radioactive waste facilities housed at the site.
Director general Mariano Grossi said: “I’m deeply concerned about the difficult and stressful situation facing staff at the Chernobyl nuclear power plant and the potential risks this entails for nuclear safety.
“I call on the forces in effective control of the site to urgently facilitate the safe rotation of personnel there.”
The Zaporizhzhya was attacked by Russian forces last week and is the largest in Europe.
During the attack on the plant, a large fire sparked in what the US embassy in Kyiv called an act of terror.
He added: “If there is an explosion, it is the end of everything. The end of Europe.”
Ukraine’s national security service also claimed Russian forces had attacked a physics institute in Kharkiv.
The Kharkiv Institute of Physics and Technology houses a nuclear research facility called Neutron Source.