Russian forces are planning to begin public executions in an effort to break the morale of Ukrainians resisting their invasion, according to a European intelligence official who spoke with multiple U.S. news publications.

The unnamed official, who spoke to Bloomberg, said the Russian government has devised plans to erode the morale of the Ukrainian people, who for a week now have held out against a full-scale Russian invasion force. The plan reportedly includes cracking down on protests, detaining opponents of Russia, and even carrying out public executions.

Fox News national security correspondent Jennifer Griffin also tweeted that a European official told the news channel that Russia’s federal intelligence agency, the Federal Security Service (FSB), developed the plans.