Local officials say they received a call at 5.15pm local time (10.15pm GMT).
Both the Washington DC Fire crew and medical service on stand by.
According to local news station Fox News 5 DC, the secret service is currently investigating the package.
Pennsylvania Avenue from 15th to 17th street has been closed.
Crucially, Pennsylvania Avenue is the main road that passes in front of the White House.
More to follow…