Several individuals accused of orchestrating a violent plot set for Halloween weekend were taken into custody on Friday in Michigan, according to a social media statement from FBI Director Kash Patel.

The operation was concentrated in the suburbs surrounding Detroit.

Patel indicated that further details would be disclosed at a later time.

Sources familiar with the ongoing investigation, who requested anonymity due to the sensitive nature of the case, informed The Associated Press that the scheme appeared to be motivated by Islamic State ideologies. Authorities are probing whether the suspects were radicalized through online channels.

In a neighborhood near Fordson High School in Dearborn, both FBI and state police vehicles were observed.

Individuals clad in FBI-branded attire were seen entering and exiting a residence, with one person noted for retrieving paper bags and other materials from an evidence vehicle.

Police in Inkster, another suburb, said FBI personnel were at a storage facility there.

“There is no current threat to public safety,” said Jordan Hall, an FBI spokesperson in Detroit, who declined further comment.

The investigation involved discussion in an online chatroom involving at least some of the suspects who were taken into custody, people familiar with the investigation told AP.

The group had discussed carrying out an attack around Halloween, referring to “pumpkin day,” according to one of the people.

The other person briefed on the investigation confirmed that there had been a “pumpkin” reference.

It wasn’t immediately clear if the group had the means to carry out an attack, but the reference to Halloween prompted the FBI to make arrests on Friday, one of the people said.

Michigan Gov. Gretchen Whitmer said on X that she was briefed by Patel.

She said she was grateful for “swift action” but offered no details.

Residents in the Dearborn neighbourhood watched as investigators worked at the house.

“It’s really scary because we have a lot of relatives around this neighborhood,” said Fatima Saleh, who was next door.

Separately, in May, the FBI said it arrested a man who had spent months planning an attack against a US Army site in suburban Detroit on behalf of the Islamic State group.

The man, Ammar Said, didn’t know that his supposed allies in the alleged plot were undercover FBI employees.

Said remains in custody, charged with attempting to provide support to a terrorist organisation.

The criminal complaint was replaced in September with a criminal “information” document, signaling that a plea agreement could be possible in the months ahead.