Ukraine's energy agency has warned a nuclear power plant currently controlled by Vladimir Putin's troops is in danger of "hydrogen leakage and sputtering of radioactive substances".
Energoatom - a state-run agency which runs all four of Ukraine's nuclear facilities - revealed that two power units at Zaporizhzhia have been reconnected to the country's grid.
But despite the positive development, the Russian military's presence means there are "serious risks" looming.
The Kremlin's troops grabbed Europe's largest power plant early on in the invasion in March, and have been stationed there with explosives and other military hardware ever since.
The agency wrote on its website: "At the same time, due to the presence of the russian military, their weapons, equipment and explosives at the power plant, there are serious risks for the safe operation of the ZNPP.
"As a result of periodic shelling, the infrastructure of the power plant has been damaged, there are risks of hydrogen leakage and sputtering of radioactive substances, and the fire hazard is high."
The statement added that Ukrainian staff members are doing whatever they can to reduce the danger and "eliminate the consequences of [shelling] damage".
Energoatom went on to accuse Putin's forces of increasing pressure on Ukraine's personnel to stop them "disclosing evidence about the crimes of the occupiers at the plant".
"Ukraine calls on the world community to take immediate measures to force russia to liberate the ZNPP and transfer the power plant to the control of our country for the sake of the security of the whole world," the agency concluded.
Yesterday, Ukrainian President Volodymyr Zelensky said Europe narrowly avoided a radiation disaster as the Russian-occupied nuclear plant was disconnected from Ukraine's power grid on Thursday.
World leaders have been worryingly watching the Zaporizhzhia site since Russian army vehicles began rolling in.
Russian shelling on Thursday night in a nearby coal power station disconnected the reactor complex at the nuclear plant from the power grid.
It temporarily cut Zaporizhzhia off from the national grid for the first time in its history.
Mr Zelenskyy said backup electricity kicked in and ensured a power supply kept the plant operating safely safe.
The Kremlin's plan to disconnect it entirely would raise the risk of a catastrophic failure by leaving it dependent on a single source of electricity to cool the reactors.
Zelensky said: " Russia has put Ukraine and all Europeans in a situation one step away from a radiation disaster."
"If our station staff had not reacted after the blackout, then we would have already been forced to overcome the consequences of a radiation accident," he continued in his nightly address.
There are fears over continued fighting near the plant, which is the largest nuclear plant in Europe, with the prospect of another accident like the disaster at the Chernobyl nuclear plant in 1986.
Vladimir Rogov, a Russian-appointed official in the occupied town of Enerhodar near the plant, blamed Ukraine's armed forces for a fire in a forest near the plant for the disconnection of power.
Russia seized control of the Zaporizhzhia plant right at the start of the war in March but it is still run by Ukrainian workers.
The United Nations is calling for the area to be demilitarized and have been pressuring Moscow to all their inspectors to visit.
“In any case, we won’t allow Russians to bring the world to the nuclear catastrophe and we will do everything just to return the plant to under our full control and operate it safely reliably, like it always been", Petro Kotin, the head of Ukraine’s atomic energy company, told the Guardian.
