Federal prosecutors have charged two men tied to what they allege was an ISIS-inspired plot based out of Michigan to carry out an attack in the US, according to a court document made public on Monday.

Mohmed Ali and Majed Mahmoud each purchased firearms, including AR-15-style rifles, in recent months and participated in online conversations indicating they had knowledge of an attack plot, according to an FBI affidavit.

Ali and Mahmoud were each charged under a federal law that bars attempting or conspiring to transfer firearms and ammunition that the person believes would be used in a crime of terrorism, in this case providing material support to ISIS.

The pair have not yet entered pleas. A lawyer for Ali did not immediately respond to a request for comment and attorney information for Mahmoud was not immediately available.

Prosecutors allege that five people, including at least one juvenile, were involved in the plot though only two are so far facing federal charges. The group used encrypted messaging platforms and social media to share ISIS-related messages encouraging attacks, according to court documents.

US authorities allege both men practiced shooting firearms at gun ranges in recent weeks and appeared to set October 31, Halloween, as the date for the attack, according to the FBI affidavit.

The document does not identify any specific targets for the alleged plot.

FBI Director Kash Patel said on Friday in a post on X that authorities had thwarted a potential attack planned for Halloween weekend, the day before the two men were formally charged and three days before the criminal complaint was made public.

Patel's post generated concern within the Justice Department that the investigation should have reached a more advanced stage before it was publicly disclosed, according to two sources briefed on the matter.