What has happened so far:
> An explosion happened onboard a District line train bound for central London around 8:20 am (local time), at the Parsons Green station.
> The London Metropolitan Police declared it a "terror incident".
> The probe which was being handled by the British transport police (BTP), was taken over by the Scotland Yard's counter terrorism command.
> The police asked for more information from eyewitnesses and said probe was still on.
> PM Theresa May to chaired a high-level COBRA meeting.
> 22 people were injured and were being treated at various hospitals. However, none are thought to be in life-threatening or serious condition.
> Media reports suggest that the attacker has been identified of using CCTV footage and that a manhunt is underway.