Rebels in Ukraine are working to develop a radioactive dirty bomb with the help of Russian nuclear scientists, according to a Ukrainian security service dossier obtained by The Times.

The report draws on hacked emails between rebels and intercepted radio communications, as well as a field agent’s findings. It claims that Russian specialists have withdrawn radioactive industrial waste from a secure bunker at the Donetsk state chemical plant and moved it to a rebel military base, where it can be combined with explosives to create a devastatingly effective weapon.

Three of the messages are said to be between Alexander Zakharchenko, head of the self-proclaimed Donetsk People’s Republic (DPR), and his ministers and generals. Conversations between rebel commanders are cited as evidence that the radioactive