Two men have been arrested by FBI and indicted on weapons charges near St.Louis, Missouri. According to CBS news source the suspects were allegedly plotting to set off pipe bombs amid the ongoing Ferguson protests.

Another law enforcement official confirmed to Reuters that two men were suspected of buying explosives which they planned to detonate during protests in Ferguson.

The suspects were arrested by the federal agents on Thursday as part of an undercover operation in St. Louis after they attempted to buy firearms under false pretenses, according to the unsealed federal indictment. The official source told Reuters on condition of anonymity that the suspects were trying to acquire explosives for pipe bombs.