The London Metropolitan Police immediately closed Ponton Road outside of the embassy in "an abundance of caution," according to their statement, before they destroyed it in a controlled explosion.
"We're aware of speculation online about an incident in the vicinity of the US Embassy in Nine Elms," the Met Police said. "Cordons are in place in the area as a precaution while officers investigate a suspect package."
Authorities updated the situation approximately an hour later after reports of a "loud bang" began circulating online.
"We can confirm that the 'loud bang' reported in the area a short time ago was a controlled explosion carried out by officers. Enquiries are still ongoing and cordons will remain in place for the time being," police said.
The embassy returned to "normal business operations" shortly after the package was destroyed, police said.
"The US Embassy is back to normal business operations, with the exception that all public appointments (visa appointments, passport appointments, and other American Citizen services) for 22 November have been cancelled," the Met Police said.
The U.S. embassy in London moved to a brand-new purpose-built location in January 2018. The 12-story government office -- complete with a moat surrounding it -- cost approximately $1 billion to construct and was funded entirely from proceeds of sale from other U.S. government property in London, according to the U.S. government.