Whitehall was evacuated and cordons put in place after a "suspicious package" was identified in Westminster.
Met Police officers responded to calls at 11.27pm today in relation to the item on Parliament Street.
A controlled explosion using a bomb disposal robot was performed.
A spokesperson told the Mirror that multiple cordons were in place with specialists on the scene.
They said: "We have the suspicious package, we have got officers on the scene and we waiting to get confirmation [as to what it is].
"Until we get a yes or no, we can't say anymore."
They added: "There a number of cordons in the area, we are not listing all of them, it's not something we would do - partly because they could change quickly."
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At just after midday Westminster MPS tweeted about the incident.
It said: "Safety cordons have been established at #ParliamentStreet #Westminster while officers investigate a possible suspicious package.
"Please bear with us while we deal with this item."
Just before 12.45pm, the force then confirmed in a follow up tweet the incident was resolved.
"Road closures and cordons are being lifted after a suspicious package was dealt with at #ParliamentStreet #Westminster," it said.
"The item was found to be non suspicious.We thank the public for their co-operation while we dealt with the item."
There were reports of a controlled explosion but these have not been confirmed by the Met.
It comes after Trafalgar Square was evacuated by police following reports of a suspicious vehicle on Saturday.
Numerous eyewitnesses claim to have heard a loud bang, although police refused to confirm reports of an explosion, or whether it was a controlled explosion, and instead have said "the incident has been resolved".
Tourist Sarah Churchill who was in Trafalgar Square at the time, with her 11-year-old son Noah, told the Mirror: "I was in the square when the bomb went off."
She said: "There were lots of police, were were just about to walk through the square when we got to corner we saw it was cordoned off.
"We were speaking to a policeman when the bomb went off without any warning."
Meanwhile, in February, a mile-long stretch of central London - including key bridges - was closed in a massive police lockdown.
The Met operation on February 15 stretched roughly one mile in South Bank along the River Thames, with the force saying it was a precaution while they assessed an unattended item.
The bridges were Westminster Bridge, Waterloo Bridge and the Hungerford and Golden Jubilee footbridges.
The force said it had been alerted to the situation at just after 10.15am on Tuesday - though it's unclear what the package actually was.
Photos show crowds of people being led off Waterloo Bridge, as well as officers stopping people crossing Jubilee bridge.
National Rail said trains were unable to run between London Charing Cross, Waterloo East and London Bridge due to the security alert.
