British authorities on Tuesday swarmed the scene outside the Houses of Parliament after a car slammed into pedestrains and protective barriers.
The male driver has been detained and police are investigating. It is unclear how many people were injured.
Ewalina Ochab, a witness, told the Press Association that the collision appeared to be deliberate.
“I was walking on the other side [of the road]. I heard some noise and someone screamed. I turned around and I saw a silver car driving very fast close to the railings, maybe even on the pavement,” she reportedly said.
There are “dozens” of armed police at the scene, Sky News reported.
No other details were immediately available, but Metropolitan Police said on Twitter that they will issue more information when they have it.
The entry at Westminster station has been closed for entry due to the security threat, police said.
This is a developing news story. Check back for updates.