Two men aged 25 were arrested on Sunday night in Mansell Street in Tower Hamlets, in a pre-planned intelligence operation conducted by Counter Terrorism Officers.
The men, one of Turkish origin and the other of Algerian origin, are still being questioned under custody along with the two other suspects.
ITV News suggested that the arrests could be connected to Syria.
The Met were unable to comment on the nature of the terror plot at this time.
Police used ‘Hatton rounds’ shotgun shells, which are used to destroy locks without risk of ricocheting, during the arrest on Mansell Street.
The London Evening Standard talked to City of London Councillor John Fletcher, who said he heard two loud bangs which he thought were fireworks.
Another local resident, Catherine Delgado, 43, told the Standard “five or six” cars circled the suspects’ vehicle. She said the police shouted at the driver to get out of the vehicle but he refused.
The two other suspects are a British national aged 28 of Azerbaijani origin, arrested in Bayswater, and a British national of Pakistani origin arrested in Peckham.
The Met confirmed that searches are still on going on six properties and two cars.
A spokesperson for the Met said: “Public safety remains our overriding concern.”