MI6 was cordoned off after a suspicious package was found in the vicinity of the London security services building.
A large area around the Albert Embankment in south London, including Vauxhall Bridge, was shut off.
A Transport For London press officer, however, said all roads were reopened shortly before 3.15pm.
A Metropolitan Police service spokesman followed, by saying at around 4pm that the operation had been "stood down" because the package was non-suspicious.
A Met Police spokesman initially said: "Officers are on the scene of a suspicious package in Vauxhall.
"Local roads are closed in the area and we are not discussing anything further at this stage."
An eyewitness wrote on Twitter: "My building, MI6 and Vauxhall bridge suddenly shut down by the police. Should I be worried?"