A 23-year-old Milwaukee resident charged with illegally possessing machine guns and a silencer had planned a mass shooting targeting a Masonic temple in the city, the FBI said Tuesday.

Samy Mohamed Hamzeh was arrested Monday after buying two automatic weapons and a silencer from undercover agents, the FBI said.

The investigation thwarted an attack “that could have resulted in significant injury and/or loss of life,” Special Agent in Charge Robert J. Shields said in a written statement.

Check back for more information on this developing story.