The invading army “shot the Kharkiv Institute of Physics and Technology,” which is said to house nuclear material and an experimental reactor, government-affiliated news outlet Ukraine NOW reported via Telegram on Sunday, citing Ukraine’s security service, SBU.

Emine Dzheppar, Ukraine’s first deputy minister of foreign affairs, criticized the attack on Twitter and said, in translation, that the attackers had used “multiple rocket launchers.”

The extent of the damage to the facility or to the alleged nuclear material inside is unclear. Ukraine NOW reported that damage to the stored nuclear material “could lead to a large-scale environmental disaster.”