Russian forces shelled a nuclear research institute in Kharkiv, Ukraine’s second-largest city on Thursday, setting buildings on fire, an adviser to Ukraine’s Interior Ministry said, according to The Associated Press.

The adviser, Anton Gerashchenko, said a shell hit a building where there is equipment that could release radiation if it were damaged. According to the president´s office, there has been no change in the background radiation.

The shelling caused a fire, but firefighters were able to put it out, according to AP.

The incident came hours after the head of the International Atomic Energy Agency (IAEA) said that Moscow and Kyiv are "ready to work" with the UN atomic watchdog to ensure nuclear safety.

IAEA director general Rafael Grossi met Ukraine's Foreign Minister Dmytro Kuleba and Russia's Foreign Minister Sergei Lavrov in separate meetings in Antalya in Turkey.

"We had good meetings, not easy ones, but serious meetings," he told reporters after returning to Vienna, where the IAEA is based, according to AFP.

"Both sides agree... that something needs to be done. They are both ready to work and to engage with the IAEA," added Grossi, who said he would try to "have something more concrete" in the next few days.

"It's a very dire situation and we need to move fast," he said.

On the first day of the Russian invasion of Ukraine, Russian forces seized the spent nuclear fuel and radioactive waste facilities at Chernobyl, the site of the world's worst nuclear accident at a now-defunct power plant.

Last week, the Russians captured the Zaporizhzhia nuclear facility after it was hit by artillery fire and set ablaze.

The IAEA has said it has lost data transmission from both Chernobyl and Zaporizhzhia, which is Europe's largest nuclear plant.

It was also not possible at the moment to bring necessary spare parts, equipment or specialized personnel to Zaporizhzhia to carry out planned repairs, the IAEA said Thursday.

Ukraine has four active nuclear power plants, providing about half the country's electricity, as well as stores of nuclear waste such as the one at Chernobyl.