A bulletin issued by the Federal Bureau of Investigation (FBI) and Department of Homeland Security (DHS) is warning law enforcement agencies over an increased number of threats calling for “civil war” and one, in particular, indicating a “dirty bomb” would be placed in front of FBI headquarters, following their raid of former President Trump’s Mar-a-Lago home.

NBC News reported on the bulletin over the weekend, citing two senior law enforcement sources.

“The FBI and DHS have observed an increase in threats to federal law enforcement and to a lesser extent other law enforcement and government officials following the FBI’s recent execution of a search warrant in Palm Beach, Florida,” the letter reportedly reads.

CBS News followed up by reporting the memo addresses online and social media threats issuing general calls for “civil war” and “armed rebellion” as well as “a threat to place a so-called dirty bomb in front of FBI Headquarters.”

The National Regulatory Commission defines “dirty bombs” as combining “a conventional explosive, such as dynamite, with radioactive material.”