Fighting has stopped near the Zaporizhzhia Nuclear Power Plant on Friday and radiation levels are currently normal.
Zaporizhzhia power plant spokesperson Andrey Tuz said the plant has not sustained any critical damage, although only one power generation unit out of six is operational as the fire continued at the facility.
As per Eastern European media, NEXTA, there was no threat of radiation spread.
'According to Andrey Tuz, spokesman of the press service of the nuclear power plant, there is no threat of radiation spread,' tweeted NEXTA.
Earlier on Friday, Ukrainian officials said firefighters were unable to access the nuclear plant.
Tuz said when firefighters initially arrived, they were met with guns and turned around.
Ukrainian authorities said about 2.30 am local time Friday that a fire had broken out at the nuclear power complex, located in Enerhodar, southeastern Ukraine.
The plant is the largest of its kind in Ukraine and contains six of the country's 15 nuclear energy reactors, according to the International Atomic Energy Agency (IAEA).
United States Secretary of Energy Jennifer Granholm tweeted on Thursday night that she spoke with Ukraine's energy minister about the situation at the Zaporizhzhia nuclear power plant.
The US has activated its Nuclear Incident Response Team, and is monitoring the situation along with the Department of Defence, the US Nuclear Regulatory Commission and the White House, she said.
"We have seen no elevated radiation readings near the facility. The plant's reactors are protected by robust containment structures and reactors are being safely shut down," she said.
"Russian military operations near the plant are reckless and must cease," she added.
The International Atomic Energy Agency (IAEA) said in a tweet on Friday that 'essential' equipment at the Zaporizhzhia Nuclear Power Plant site has not been affected by the fire, according to Ukrainian authorities.
It added that the 'plant personnel (are) taking mitigatory actions'.
US President Joe Biden received an update from Ukrainian President Volodymyr Zelensky late Thursday night about the reported fire at the Zaporizhzhia nuclear plant, the White House said in a statement after the two leaders' phone call.
Biden joined Zelensky 'in urging Russia to cease its military activities in the area and allow firefighters and emergency responders to access the site', according to the statement.
Biden also received an update on the situation from the undersecretary for Nuclear Security of the US Department of Energy and the Administrator of the National Nuclear Security Administration (NNSA).
The Zaporizhzhia nuclear power plant is the biggest in Europe according to the plant's website. It supports one-fifth of the total electric power generated in Ukraine.
The nuclear plant has six units in total, with the first one connected to the power grid in 1984, and the sixth one connected in 1995.
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