UK Parliament attack
In picture: Armed police respond outside Parliament during an incident on Westminster Bridge in London, Britain March 22, 2017.Reuters

The whole world sat up and watched on in horror as a terrorist attack unfolded near the UK Parliament. While details of the attack are still coming out, initial reports say all the MPs are safe, but three people -- a woman, a policeman and an assailant -- have been killed in the attack.

Also read: UK Parliament attack: 'Terrorist' shot dead after stabbing policeman, running over pedestrians on Westminster Bridge

There have also been reports of "catastrophic" injuries to some. Here is what we know so far:

* The London Metropolitan Police responded to what they described in a tweet as a "firearms incident" on Westminster Bridge at 2:40 pm local time (8:10 pm IST).

* Some time later, they said: "We are treating this as a terrorist incident until we know otherwise." It was initially suspected tht there were two attackers.

* They also asked people to avoid Parliament Square, Whitehall, Westminster Bridge, Lambeth Bridge, Victoria Street up to the junction with Broadway, and the Victoria Embankment up to Embankment tube.

* In an update, they said: "There are a number of casualties including police officers." However, they did not give a number at the time. French Prime Minister Bernard Cazeneuve later said some French students, who were on a school visit to London, were also hurt in the attack.

* Eyewitnesses also said they saw a car plough into several people near the UK Parliament, injuring at least five people.

* Local reports said the police shot an assailant near the UK Parliament. Other reports said a woman died in the attack. Subsequent reports said one of the police officers stabbed in the attack died on the spot after failed attempts to revive him. The death toll is now three.

* UK Prime Minister Theresa May is said to be safe: She was reportedly ushered away in a car under tight security.

* The London Metropolitan Police have released phone numbers on Twitter through which people can report suspicious activity. It said: "Please report anything suspicious to the Anti-Terrorist Hotline 0800 789 321. In an emergency call 999."

Here is the rescue video of the incident:

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