Police have reportedly performed a controlled explosion near Westminster, less than a mile away from the scene of a terrorist attack which claimed the lives of four people.
The Metropolitan Police said officers found an unattended bag in Birdcage Walk, which runs between Westminster and Buckingham Palace.
It came less than two days after terrorist Khalid Masood killed four people by driving through pedestrians on Westminster Bridge and trying to storm Parliament.
A Metropolitan Police spokesman said: "Police are dealing with a suspect package in the area of Birdcage Walk. Officers remain at the scene."
The spokesman did not confirm whether a controlled explosion had been carried out.
The Met said on Twitter: "Unattended bag found Birdcage Walk/Horseguards was not suspicious. All cordons put in for safety being lifted. Thanks for your patience."
The reported explosion came during a BBC News live broadcast. Senior producer Pia Talbot tweeted: "Police say they've just carried out a controlled explosion within earshot of our live spot."
Sky News reporter Laura Bundock tweeted there was a "very loud bang close to security cordon where suspicious package found".
Masood is thought to have regularly attended a mosque in Birmingham, although security sources refused to discuss details because, they said, it was part of ongoing investigations.
Scotland Yard said eight people – five men and three women – had been arrested in London and Birmingham and were being held on suspicion on preparing terrorist acts.
Detectives are continuing to search a number of addresses in relation to the attack, including three properties in Birmingham, one in east London, and one in Carmarthenshire, Wales.
Isis claimed the attacker was a "soldier of the Islamic State" when it claimed responsibility for the attack.
However the group did not name him and did not provide any further details. The terrorist group regularly claims “credit” for atrocities and there is no evidence at present to verify the claim.