Suspicious packages were sent this week to election offices in more than 20 states, leading to an FBI investigation, triggering evacuations and rattling staff, according to a CNN survey of state offices and Associated Press reporting.

The Federal Bureau of Investigation, along with the U.S. Postal Inspection Service, are investigating suspicious packages that were delivered to election officials in several states, according to officials.

The FBI and U.S. Postal Service are investigating suspicious packages that have been sent to or received by elections officials in at least eight states.