WASHINGTON — The Washington, D.C. campaign office of GOP Presidential candidate Marco Rubio was briefly evacuated Tuesday after a suspicious white substance was discovered by staff.

Rubio spokesman Alex Conant told ABC News, ‘Employees have evacuated to the roof of the D.C. office building, while hazmat crews are in the office.’

The FBI was aware of the incident and were also responding. An ‘all-clear’ has since been given.