(CNN) -- A joint terrorism task force is investigating the origins of a suspicious package that contained "explosive components" found inside a Federal building in Detroit.
The package was discovered Friday at the Patrick V. McNamara Building, which houses offices of the FBI, the Internal Revenue Service and other federal agencies, according to Department of Homeland Security spokesman Chris Ortman.
"This is an ongoing investigation," said FBI Special Agent Sandra Berchtold. "The priority now is to determine what it was and who left it there."
The package was taken from the McNamara building, which was not evacuated, and detonated at Detroit's Belle Island, said police spokesman Samuel Balogun.
The contents of package were not immediately clear.
An FBI Terrorism Task Force is leading the investigation in collaboration with DHS and Detroit Police in an effort to "determine the origins of the package contents and ensure that those responsible are brought to justice," Ortman said.
No arrests were reported.