Five people were killed and over 40 people remain in hospital, some in a serious condition, after an attacker drove a 4WD vehicle into crowds on the nearby Westminster Bridge in London overnight. Britain's Parliament was locked down after the attacker stabbed and killed a nearby police officer. For the latest information, stay up to date with 1 NEWS Now and our news bulletins at 6pm and 10:30pm on TV1.
The attack on the British Parliament is an attack on parliaments, freedom and democracy everywhere. Westminster is rightly known as the mother of parliaments.- Australian Prime Minister Malcolm Turnball
3:05pm: Australian Prime Minister Malcolm Turnball has offered "Australia's heartfelt sympathy and resolute solidarity" to the people of the United Kingdom. He said he increased police presence in Parliament House in Canberra today as a result of the attacks.
2:43pm: President Donald Trump has tweeted for the first time about the attack in Westminster. A tweet was sent from the @POTUS account earlier today, which is run by White House Staff.
2:00pm: BBC reported that four students from Edge Hill University in Lancashire were injured in the attack while on a visit to the Houses of Parliament.
12.45pm: Cordons now being lifted at Lambeth Palace Rd and York Rd.
12.36pm: Tel Aviv City Hall lights up in solidarity with the UK.
12.32pm: Lights on the Eiffel Tower in Paris extinguished to honour the victims of the Westminster attack.
12.26pm: BBC reported that five South Korean tourists were injured in the attack, one of them seriously.
The South Korean tourist with a serious injury was identified as a 67-year-old woman, and it being treated at St Mary's Hospital.
12.21pm: Kiwi woman working close to the scene of the Westminster terror attack talks about how "it could be any of us".
Tonight all Londoners are grateful to them.- London mayor Sadiq Khan.
12.16pm: London Mayor Sadiq Khan offered his own tribute to Keith Palmer who, he said, "personifies the brave men and women of our police and emergency services".
12.12pm: MP who was a friend of fallen police officer Keith Palmer offered a personal tribute.
11.55am: Paris mayor Anne Hidalgo said the Eiffel Tower will go dark tonight (in less than an hour) to honour the victims of the Westminster attack.
11.43am: Police release a photo of the police officer killed in Westminster attack.
11.29am: Latest from National Lead for Counter-Terrorism Mark Rowley: The Police officer who died has been identified as PC Keith Palmer. Approximately 40 people have been injured, including 3 police officers, 2 seriously injured. The death toll has increased to five.
11.21am: Latest statement from London Ambulance: 68 paramedics and ambulance crews responded to the terrorist attack.
11.12am: PM Bill English issues a statement "utterly condemning" the attack.
11.00am: A counter-terrorism expert said it was likely the Westminster attack was timed to coincide with the bombing anniversary of Brussels.
10.41am: Muslim Council of Britain issues a statement condemning the attack.
10.37am: ITV reports that the Queen will not go ahead with plans to visit the new Scotland Yard headquarters tomorrow.
10.30am: Police remind Londoners that there will be heightened presence of both armed and unarmed police officers following the attack.
10.20am: Read the story of the British MP Tobias Ellwood who's being hailed as a hero for his attempt to resuscitate the police officer who was stabbed here.
10.00am: PM Theresa May speaks to the media, saying UK's terrorist threat level will remain at severe.
We will all move forward together, never giving in to terror, and never allowing the voices of hate and evil to drive us apart.- British PM Theresa May
"The values our Parliament represents - democracy, freedom, human rights, the rule of law, command the admiration of free people everywhere. That is why it is a target for those who reject those values."
9.41am: 400 MPs gave rousing applause to police and security services when finally allowed to leave the Commons chamber.
9.27am: US President Trump expresses his condolences.
9.20am: The Ministry of Foreign Affairs said there is "no indication at this stage to suggest New Zealanders have been caught up in the incident".
Today's attack on the UK Parliament is an attack on democracies around the world.- Canada PM Justin Trudeau
9.18am: Canadian PM Justin Trudeau issues a statement on the attack, offering full support to PM May and the people of UK.
9.14am: The Press Association reported that four university students were injured as they were caught up in the attack. They were from Edge Hill University in Ormskirk and were on an educational visit to the Houses of Parliament.
9.11am: Romania's foreign ministry says two Romanians were wounded in the attack, Associated Press have reported.
9.10am: Reuters is reporting that police are still seeking one assailant in the London attack.
9.03am: Read the reaction of world leaders to the attack here.
8.54am: Latest statement from London ambulance.
8.45am: Guardian reported that the lockdown on Westminster is over, after several hours.
We stand together in the face of those who seek to harm us and destroy our way of life.- London mayor Sadiq Khan
8.27am: London mayor Sadiq Khan thanks emergency services and expresses solidarity and unity in the face of the attack.
8.17am: Former UK Prime Minister expresses heartfelt sympathies for the victims.
8.09am: Police have set up a Casualty Bureau for those worried about family and friends, but warn that demand will be high.
8.04am: New Zealand PM Bill English said the thoughts of New Zealand are with the people of London.
8.01am: King's College NHS said its Emergency Department treated eight patients - six males and two females. Two are in critical condition and six are in stable condition.
7.58am: Flag flown at half-mast over Scotland Yard to mark the death of the police officer and the other victims of the attack.
7.56am: No. 10 Downing St issues a statement from PM Theresa May. COBR, often referred to as Cobra, is a crisis response committee.
7.49am: British Opposition leader Jeremy Corbyn thanks the police and emergency services for their hard work.
7.42am: BBC reported that five of the injured have been taken to the major trauma centre at Kings College Hospital London.
7.37am: Police are in the process of opening the Casualty Bureau to help those who are worried about friends or family following the attack.
7.28am: Guardian reports that two of the high school French students hurt in the attack are in critical condition.
7.21am: US Secretary of State Rex Tillerson expresses his condolences for the victims of the attack and their families.
This is an attack that London has been waiting for, and it has finally arrived.- 1 NEWS Europe Correspondent Emma Keeling
7.00am: National Lead for Counter-Terrorism Mark Rowley said at a press conference that four people are dead, including the police officer who was stabbed and the man believed to be the attacker. At least 20 people have been injured and police currently believe there was only one attacker.
My thoughts are with everyone caught up in the dreadful incident at Westminster today, including the emergency services who responded bravely.- Nicola Sturgeon
6.56am: Scotland's First Minister Nicola Sturgeon issued a statement about the attack.
6.51am: Reuters said French officials confirm three French schoolchildren, aged around 15 to 16, on a school trip were hurt in the attack.
6.46am: US President Trump and May speak on the phone following the attack.
6.40am: BBC understands from multiple sources that there were two assailants in the vehicle on Westminster Bridge.
6.35am: The BBC and multiple UK media organisations are reporting that two people are dead. The first fatality was a female pedestrian. It is being reported the second fatality is the police officer who was stabbed.
6.28am: AFP says French students have been hurt in the London attack.
6.25am: Former British PM tweets his reaction.
6.17am: British PM Theresa May to hold emergency security meeting after London attack.
6.10am: Port of London authority has told the Guardian that a woman has been recovered from the Thames river with serious injuries and is undergoing medical treatment.
6.05am: Parliamentary lobby is being evacuated.
6.03am: London Ambulance has treated at least 10 patients on Westminster Bridge.
6.00am: Metropolitan Police Commander says a "full counter-terrorism investigation is under way".
5.51am: 1 NEWS Europe correspondent Emma Keeling describes the scene of the attack,
5.48am: Metropolitan police confirms that "there are a number of casualties, including police officers. More police to be deployed.
5.45am: Foreign Minister Tobias Ellwood attempts to resuscitate the stabbed policeman, the Telegraph reports.
5.38am: London Metropolitan police are appealing for pictures or video footage of the incident.
5.30am: London mayor Sadiq Khan has spoken to the Acting Commissioner.
London police said they were treating the attack as a "terrorist incident until we know otherwise."