U.S. Senator Joe Lieberman's office in his home state Connecticut was targeted by suspicious mail, the latest in a string of similar incidents, U.S. media reported on Friday.

The Hill newspaper, which specializes in reporting Congressional affairs, quoted Lieberman's spokeswoman Whitney Phillips as saying on Thursday afternoon, that staff at Lieberman' s district office in Hartford, Connecticut, received a suspicious package.

The package had specific address information matching a warning given to Congressional offices earlier this week. According to an email sent to Congressional offices by Senate Sergeant at Arms Terry Gainer on Wednesday, letters postmarked from Portland, Oregon, or with a specific return address containing The MIB, LLC. may contain "a suspicious powdery substance". The warning was prompted by threatening mail that contained the substance received Tuesday by a Senate State office and a House District office.

"Yesterday when our staff in our state office was sorting the mail -- around the lunchtime hour -- they came across a package with the same return address," Phillips was quoted as saying.

She said the staff secluded the package, closed off the room, and notified local authorities and the FBI.

Authorities then evacuated the office, and initial tests of the envelope's contents came back negative for harmful material. Phillips said Lieberman himself was out of the office, but in the state, at the time of the evacuation Thursday.