Washington DC - More information has come out about a suspicious and potentially dangerous package sent to a military base after it was linked to the possible illness of multiple people.

Seven people briefly felt ill after a suspicious package was opened on Thursday at the military base near the US capital that is home to Air Force One, the presidential jet, a base spokesperson said Friday.

The package contained "negative sentiments" towards President Donald Trump, but there were "no specific threats towards the president or other government officials," the spokesperson for Joint Base Andrews said in a statement.

"Emergency responders evacuated the building and connecting building and established a cordon around the area," the statement said. "Seven individuals felt ill and were assessed by the JB Andrews medical team and were released."

The spokesperson said testing was conducted for contaminants, but "no powder or hazardous materials were found and there is no active threat."

The media had reported previously that the package contained a white powder.

Joint Base Andrews in Maryland is a short drive from Washington and is used by senior US government officials.

Trump landed at the facility as recently as Wednesday on an Air Force One flight returning him from a business forum in Florida.

According to CNN, the package was opened in a building that houses the Air National Guard Readiness Center on the sprawling base.