London attack: What we know so far about Khalid Masood and Westminster terror probe
A massive police operation is under way after a terror attack in Westminster in the heart of London.
This is what we know so far:
:: Five people have died - Pc Keith Palmer, 48, mother-of-two Aysha Frade, US tourist Kurt Cochran and Leslie Rhodes, 75, from Clapham, south London. The attacker, Khalid Masood, also died.
:: Masood, 52, had a string of criminal convictions including possession of a knife, but he was not the subject of any current investigations and there was "no prior intelligence about his intent to mount a terrorist attack".
:: Masood was born Adrian Russell Elms in Dartford on Christmas Day 1964.
:: He later used the name Adrian Ajao after his mother married Phillip Ajao in 1966.
:: The attacker was investigated by MI5 some years ago over concerns of violent extremism.
:: Eleven people have been arrested and a number of addresses raided across London, Birmingham and elsewhere. Ten people remain in custody and one, a woman, has been released on bail.
:: Those arrested include a 39-year-old woman held at an address in east London the night after the attack on suspicion of preparation of terrorist acts and later bailed.
:: A 21-year-old woman and a 23-year-old man were also arrested at an address in Birmingham the night after the attack on suspicion of preparation of terrorist acts.
:: A 26-year-old woman and three men aged 28, 27 and 26 were arrested at a separate address in Birmingham the night after the attack on suspicion of preparation of terrorist acts.
:: A 58-year-old man was arrested on Thursday morning at a separate address in Birmingham on suspicion of preparation of terrorist acts.
:: A 27-year-old man was arrested late on Thursday in Birmingham and a second man, aged 35, was held in Manchester in the early hours of Friday.
:: A 32-year-old woman was arrested in Manchester on Friday morning.
:: The woman killed on the bridge was Ms Frade, who worked at DLD College London.
:: Mr Cochran, 54, from Utah, was the man killed in the incident on the bridge.
:: Mr Rhodes, a retired window cleaner, died after life support was withdrawn at King's College Hospital on Thursday night.
:: At least 50 people of 12 different nationalities were injured, including 12 Britons, three French children, two Romanians, four South Koreans, two Greeks, and one each from Germany, Poland, Ireland, China, Italy and the United States.
:: One of the injured has life-threatening injuries and two others are in a critical condition.
:: Three police officers were also hurt, two of whom remained in hospital in Friday with "significant injuries".
:: Police have seized 2,7000 items in searches, including "massive amounts of computer data".
:: Approximately 3,500 witnesses, including 1,000 from Westminster Bridge and 2,500 from within the Parliamentary estate, have contacted police.
:: The Hyundai used to mow down pedestrians on Westminster Bridge was hired from a branch of car rental firm Enterprise in Spring Hill, Birmingham.
:: Attacker Masood, armed with two large knives, jumped out of the car after smashing it into the railings encircling the Palace of Westminster, fatally stabbing Pc Palmer as he entered the grounds.
:: He was shot dead moments later by another police officer.
:: Islamic State has claimed the attacker was one of its "soldiers".
:: Defence Secretary Sir Michael Fallon has said the working assumption is that the attack is linked to Islamic terrorism.
:: Prime Minister Theresa May chaired a meeting of the Government's emergency Cobra committee on Wednesday night, later branding the attack "sick and depraved".
:: Police forces around the UK are reviewing their security arrangements in the wake of the Westminster attack.