The men were charged in a grand jury indictment announced by the U.S. Attorney for the Southern District of Florida. Federal prosecutors allege the men, both U.S. citizens, provided money, housing, communications equipment and transportation as part of a conspiracy.
A statement from prosecutors said the brothers' alleged goal was "to use a weapon of mass destruction (explosives) against persons and property within the United States". It did not elaborate and U.S. officials declined to go into details but said the arrests were not the result of a sting operation.
The accused were identified as Raees Alam Qazi, 20, and Sheheryar Alam Qazi, 30. They were arrested on Thursday in Fort Lauderdale and made an initial appearance in federal court on Friday.