At least five people have been killed in a terror-related incident in London.

This is what we know about how events unfolded this afternoon.

2:45pm

Reports emerge of gunfire outside the Houses of Parliament.

2:47pm

Witnesses take to Twitter to report a car has hit at least five people on Westminster Bridge and the sound of the an explosion plus gunshots were heard outside of Parliament.

Early reports suggest two have been killed and as many as 12 others have been injured.

2:52pm

2:54pm

Press Association reports:

“There was a major security alert at the Palace of Westminster after a man apparently carrying a knife charged through the gates into the front yard of the parliamentary compound.

“Amid shouts and screams, sounds similar to gunfire rang out.

“Two people were seen to be lying within Old Palace Yard, immediately outside Westminster Hall.

“The sitting in the House of Commons was suspended while police officers sealed off the area around the incident.

“Immediately before the incident, at around 2.45pm, a crowd of passersby was seen running from the direction of Westminster Bridge and around the corner into Parliament Square.”

3:09pm

David Lidington, Commons leader, tells MPs gathered in Commons that a “police officer has been stabbed” and the “alleged assailant was shot by armed police”.

3:10pm

Video emerges of the moment police shot an armed attacker outside the Houses of Parliament.

3:19pm

Transport for London (TfL) confirms that Westminster Tube station has been closed.

The Metropolitan Police Service is on scene in Westminster.

3:18pm

Downing Street confirms that Theresa May is safe. At the sound of potential gunfire near Parliament, the Prime Minister was reportedly ushered into a silver Jaguar.

3:35pm

Police confirm that they are treating the incident as terrorism.

3:40pm

London Ambulance Service releases a statement calling the situation a “major incident”.

“We were called at 2.40pm to Westminster Bridge to reports of an incident, with the first crew arriving within six minutes.

“We have sent a number of resources to the scene including ambulance crews, London’s Air Ambulance and our Hazardous Area Response Team.

“We are working closely with other members of the emergency services at the scene, with our priority being to ensure patients receive the medical help they need as quickly as possible.

“We have declared a major incident and our priority is to assess patients and ensure that they are treated and taken to hospital as soon as possible.

“As we are very busy dealing with this incident, we would ask the public to only call us in a genuine emergency.”

3:41pm

Donald Trump “has been briefed on the situation”, his press secretary Sean Spicer says.

3:55pm

Reports say one person has been taken from Old Palace Yard in an ambulance, while another remains covered under a blanket on the cobbles, seemingly dead. It is unknown who the two people are.

4:00pm

MPs have been evacuated to New Scotland Yard.

The SNP’s Pete Wishard tweeted: “Got out of the building and into New Scotland Yard with other MPs and staff. Incredible response from emergency services.”

The public gallery has also been evacuated.

4:15pm

St Thomas’ Hospital states that one woman has died and numerous others are injured, some of whom have “catastrophic injuries”.

4:20pm

A bomb squad has been called after a suspicious package was found in a vehicle near Parliament.

4:52pm

5:25pm

BBC reports a police officer has died in the attack.

5:52pm

Primary school children who were on a trip to the Houses of Parliament are evacuated from the premises.

6:00pm

Head of counter terrorism Mark Rowley confirms four people have been killed in the attack. Included among fatalities is a police officer, the attacker and a woman who was hit by a car on Westminster Bridge.

6.27pm

Both the House of Commons and the House of Lords will sit at their normal times on Thursday, parliamentary authorities have announced.

Developing story: The latest news after the Westminster attack

Video shows aftermath of Parliament attack

Eyewitnesses recall moment car ploughed into crowd on Westminster Bridge