Federal authorities are investigating a wave of potentially hazardous mail sent to congressional and state election offices across the United States. The FBI and the US Postal Inspection Service announced they are working to trace the suspicious envelopes, some of which were intercepted before reaching their destinations.

The security scare comes just weeks before the US midterm elections. While officials declined to disclose the total number of targeted locations, several state offices reported receiving packages containing a white powdery substance. In Louisiana, an office was temporarily evacuated after a staff member opened a letter on Tuesday, though law enforcement later found no harmful materials. Similar letters were reported by election or congressional offices in Delaware, Oklahoma, Ohio, Connecticut, New York, and Wyoming, with postal inspectors intercepting several packages beforehand.