Scotland Yard said the attack in Westminster was being treated "as a terrorist incident until we know otherwise".
A police officer has been stabbed and his apparent attacker shot by officers in a major security incident at the Houses of Parliament.
Scotland Yard said in a statement: "Police are asking people to avoid the following areas: Parliament Square; Whitehall; Westminster Bridge; Lambeth Bridge; Victoria Street up to the junction with Broadway and the Victoria Embankment up to Embankment tube.
"This is to allow the emergency services to deal with the ongoing incident. "Officers - including firearms officers - remain on the scene and we are treating this as a terrorist incident until we know otherwise.
"We thank the public for their assistance."
As parliament remains in lockdown amid a continuing security incident, paramedics could be seen outside treating two people.
It is unclear who they are or how severe their injuries are.
Emergency services are at the scene after a stabbing outside Parliament.
A Conservative MP told Parliament a police officer has been stabbed and the assailant shot.
There are also emergency crews on Westminster Bridge.
The region's MPs are all thought to be safe after an apparent attack at the Palace of Westminster in London.Read the full story ›
A man who was stabbed to death in Essex has been named as Danny Myers.
Police found the 23-year-old victim at a house in Rochford Road in the village of St Osyth near Clacton on Monday (March 20).
A post mortem examination found Mr Myers, from Enfield, died from a stab wound to the heart.
A 35-year-old man from London and a 29-year-old woman from Clacton have been arrested on suspicion of murder.
A five-year-old boy has been left fighting for his life, after being hit by a car outside his home in Essex.Read the full story ›
A five-year-old boy has suffered life-threatening injuries after a suspected learner driver crashed into him in Saffron Walden.Read the full story ›
A five-year-old boy has suffered life-threatening injuries after a suspected learner driver crashed into him in Saffron Walden.
The youngster was struck by a Renault Megane on Wednesday, which then crashed into a house in Gabriel Street.
An Essex Police spokesman said: "Police believe the driver was a learner and there were L-plates on the vehicle."
The boy was airlifted to hospital where he remains in a critical but stable condition.
The driver and passenger of the vehicle have been voluntarily interviewed by police and inquiries are continuing.
Police are keen to speak to children who were with the boy at the time of the incident but have not yet spoken to officers.
A couple from Northampton have been found guilty of nearly 100 drug and child sex offences.
Nicholas and Joan Taylor abused children, some as young as 11, over a period of ten years starting in 1996.
The crimes, most of which were committed at their home in Briar Hill in Northampton, included rape and dealing in class A drugs.
They're both due to be sentenced at a later date.
The Taylors were master manipulators who used crack cocaine to force their victims to engage in sexual activity against their will and their actions have had a devastating impact on their victim’s lives.
- Anyone who may have been a victim of this type of crime and would like to speak to someone independent of the police, can contact Voice, for victims and witness in Northamptonshire, on 0300 303 1965 or find out more at voicenorthants.org
A 21-year old youth detention centre officer has been left in a coma after a violent attack in Milton Keynes.
The officer was attacked after a football match at Oakhill Secure Training Centre in Milton Keynes yesterday (Wednesday March 15) .
He was taken to hospital and placed in a medically-induced coma after surgery, following a life saving operation for his serious head injuries.
Five boys, aged between 14 and 16, have been arrested on suspicion of assault and are in custody.