The FBI is investigating several suspicious packages discovered Tuesday night at the UPS facility at Minneapolis-St. Paul International Airport.

Workers noticed three to four packages that appeared to be suspicious and contacted authorities, said FBI spokesman Kyle Loven. They were addressed to federal government entities, but he wouldn’t be more specific because of the ongoing investigation.

The facility was shutdown through the early morning Wednesday. The state Department of Health is analyzing the packages, Loven said. There have been no arrests.