BREAKING: Man mows down pedestrians in a car and a police officer is stabbed outside Parliament in suspected terror attacks

• Intruder shot by police after stabbing police officer inside the grounds of Parliament
• A car has driven into at least a dozen people on nearby Westminster Bridge
• Emergency services are at both scenes treating the injured
• Central London is on lockdown
• WARNING: Some of the images below are graphic. 

LONDON - A man has been shot by police and least dozen people are injured after being hit by a vehicle on the nearby Westminster Bridge in central London on Wednesday afternoon. 

In what the metropolitan police are currently treating as a terrorist attack, police shot an unidentified person outside the gates of parliament on Wednesday afternoon after they stabbed a police officer with a knife. 

The police officer who was stabbed is being treated at the scene. The alleged intruder has been put into an ambulance. 

"Three of four gunshots" were heard, according to the BBC. 

REUTERS/Stefan Wermuth

Police tapes off Parliament Square after reports of loud bangs, in London, Britain, March 22, 2017.

This incident took place immediately after a vehicle drove into the gates of parliament. 

At least a dozen people are also injured on nearby Westminster Bridge where a car mowed down a group of pedestrians.

The BBC's Andrew Neil is reporting that the car that mowed down people on Westminster Bridge was the same vehicle that crashed into the gates of parliament.  

The Metropolitan Police have confirmed that they were called to an incident on the bridge at around 2:40 p.m. (GMT). 

A witness close to Westminster Bridge has told Business Insider that there are "lots of sirens" and "people running" at the scene. 

All government and civil service offices are currently on lockdown and all inside have been told to remain indoors as the situation unfolds. 

PoliticsHome editor Kevin Schofield told Sky News that "someone rushed through the security gates and assaulted a policeman, appearing to have a knife in his hand".

Ambulances and emergency services are present at both sites. Westminster tube station and nearby buildings including St Thomas' Hospital and the Gherking building also on lockdown. 

Dozens of armed officers are currently inside the grounds of parliament. 

Prime Minister Theresa May is safe, a spokesperson has confirmed. 

REUTERS/Toby Melville

An armed police officer assists a woman after an incident on Westminster Bridge in London, March 22, 2017.

REUTERS/Toby Melville

A man lies injured after a shottingt incident on Westminster Bridge in London, March 22, 2017.

Reuters / Toby Melville

Business Insider/Donald Sinclair

Toby Melville / Reuters

Here is the scene at parliament after a car drove into the gate:

An emergency helicopter landed inside the ground of parliament moments ago:

 Here was the scene on Westminster Bridge earlier today:

This is the moment Parliament was suspended:

MP David Liddington told Parliament:

"The alleged assailant was shot by armed police.An ambulance is currently attending the scene, to remove the casualties. There are also reports of further violent incidents in the vicinity of the palace of Westminster, but I hope colleagues from all sides will appreciate that it would be wrong of me here to go into further details until we have confirmation from the police and from the house security authorities about what is going on. "

US President Donald Trump has been brief on the situation, his spokesperson Sean Spicer confirmed. 

This is a developing story...