The Ukrainian nuclear regulator says Russia has committed an "act of nuclear terrorism" in bombing a research facility containing a reactor.
The State Nuclear Inspectorate of Ukraine said the reactor core at the Kharkiv Institute of Physics and Technology in the city of Kharkiv had been loaded with fresh nuclear fuel just prior to the start of Russian aggression.
Russian forces carried out an airstrike on the science research centre in the Ukrainian city of Kharkiv today, sparking fears of radiation exposure, according to reports.
In a statement released this evening nuclear watchdog said they were still assessing the damage to the site, adding: "This list of injuries is not complete at this time."
They said: "Prior to the Russian aggression, the Source of Neutrons was at the stage of physical start-up, during which the core was loaded with fresh nuclear fuel.
"On February 24, 2022, the unit was transferred to a deep subcritical state by the operational personnel of the Source of Neutrons."
In a report on the state of the reactor, which is used in scientific research at the institute, the Inspecorate said critical buildings at the site had sustained damage during the attack but the reactor was currently in a "deep subcritical state" and "completely de-energized".
Video from the scene is understood to show huge flames at the centre, where the first development of a nuclear bomb was carried out in the USSR.
The shelling was carried out at around 8.20pm local time, according to witnesses.
Ukraine's Centre for Strategic Communications and Information Security posted on Twitter: "In Kharkiv, eyewitnesses report a fire in the building of Kharkiv Institute of Physics and Technology.
"The building contains equipment which, if damaged, can lead to radioactive pollution of the environment."
The building has already been hit during Russia's bombardment of Kharkiv earlier this week.
After it was first targeted, authorities said the institute is home to a nuclear research facility with 37 nuclear fuel cells.
Russian strikes risked a “large-scale ecological disaster”, security services said three days ago after the facility was reportedly targeted.
Security consultants the Cavell Group tonight tweeted: Ukraine/Russia: "Significant artillery fire again tonight on Kharkiv and reports of air activity. Reports also that a large fire is burning at the Institute of Physics and Technology after it was targeted."
Western officials fear the number of refugees fleeing Ukraine could hit 4 million as Russia continues its brutal onslaught.
The UN refugee agency briefed Western countries on Wednesday that there were now an estimated 2.2 million refugees from the conflict - and the number could rise to 4 million over the days to come.
Officials say the Russian invasion has sparked almost "unprecedented" movements of people across Europe, triggering the greatest refugee crisis since the Second World War.
One said: "I would like to stress the sheer scale of this, which is something that we haven't seen, certainly since the end of the Second World War, and that is a real challenge to us all."
It comes as Home Secretary Priti Patel was forced to streamline the visa process for Ukrainian's seeking sanctuary in Britain after a public outcry.
