A police officer has been stabbed in the Houses of Parliament in central London, United Kingdom – the parliament in lock-down

Commons leader David Lidington told MPs the “alleged assailant was shot by armed police” following a “serious” incident.

Staff inside Parliament were told to stay inside their offices and the house was put under lockdown.

“We were called at approx 2:40 pm to reports of an incident at Westminster Bridge. Being treated as a firearms incident — police on the scene,” police said on Twitter.

A staff member in parliament who did not want to be named told: “I definitely heard shots. I saw someone in dark clothing go down.”

Police told her someone had been shot and MPs said they heard “three or four gunshots“, according to the BBC.

The London Metropolitan Police tweeted it considers the incident as a terrorist incident
until proven otherwise.

Political editor for the Independent  tweeted, “There was a loud bang. Screams. Commotion. Then the sound of gunshots. Armed police everywhere.”

Scotland Yard said it was called to a firearms incident on Westminster Bridge amid reports of several people injured.

Transport for London said Westminster underground station has been shut at the police’s request.

Latest update from Twitter at 4:38 PM CET:

Ambulances still rushing to the scene of an incident outside the UK parliament building. The area is under lockdown as the situation unfolds. House of Commons leader David Lidington has said a police officer was stabbed in the houses of parliament. The alleged assailant was shot by armed police, according to Lidington.

Note: This is a developing story. Updates will follow as the incident progresses.