Updated

Authorities have arrested a 21-year-old Michigan man whom they accuse of supporting Islamic State militants and plotting to attack a Detroit church.

Khalil Abu-Rayyan, of Dearborn Heights, appeared Thursday in U.S. District Court in Detroit and is jailed pending a Monday hearing. He hasn't been charged with terrorism-related crimes but has been investigated since May and faces marijuana and gun charges.

U.S. attorney's office spokeswoman Gina Balaya said Saturday that Abu-Rayyan will have a court-appointed attorney at the hearing but she doesn't know who it is.

Balaya says Abu-Rayyan had been under constant FBI surveillance recently due to growing concern about threats he made against the church, police officers and others in support of IS. Authorities say Abu-Rayyan had been communicating with an undercover agent.