The FBI says Monday that it foiled a terrorist attack in a small Minnesota town, but details are still scarce, NPR reports.

Buford Rogers, 24, made his first appearance in U.S. District Court in St. Paul on one count of being a felon in possession of a firearm, AP reports. Authorities arrested him Friday after a search of his home turned up Molotov cocktails, as well as suspected pipe bombs and firearms. Reuters reports that an assault rifle was among the weapons found.

The FBI believes there was a localized terror attack in its planning stages, which is why law enforcement quickly executed the search warrant, according to FBI spokesman Kyle Loven. He declined to elaborate on the target, and he would not say whether Rogers was acting alone or as part of a group.