An American on holiday in Britain with his wife to celebrate their 25th wedding anniversary and a 43-year-old London woman were two of the three people killed by the London attacker.
The assailant, named as old Kent-born Khalid Masood, ploughed a car into pedestrians on London's Westminster Bridge before fatally stabbing police officer Keith Palmer inside the gates of parliament.
Masood was shot dead by police officers. He had once been investigated by the MI5 intelligence agency over concerns about violent extremism, but had been a peripheral figure.
About 40 people were injured, of whom 29 remained in hospital on Thursday evening, seven in critical condition.
Kurt Cochran, who was 54, was from Utah, and had been visiting the capital with his wife Melissa. She is in hospital with serious injuries.
According to a family statement, the couple had been celebrating their 25th wedding anniversary and were due to return to the US on Thursday.
Also dead was 43-year-old Londoner and mother of two Aysha Frade.
Mrs Frade worked at a London sixth-form college, just a few hundred metres from Westminster Bridge, where reports say she taught Spanish.
The principal at DLD College, Rachel Borland, said she was "highly regarded and loved by our students and by her colleagues"
Both Mrs Frade and Mr Cochran were killed on Westminster Bridge.
It is believed Mrs Frade was hit by the attacker's car and thrown under a bus.
PC Palmer, who was stabbed in the grounds of Parliament, was a 48-year-old father.
He was an unarmed member of the parliamentary and diplomatic protection squad, with 15 years' service.
His family said in a statement that he would be remembered as a "wonderful dad and husband".
They also described him as "a loving son, brother and uncle. A long-time supporter of Charlton FC. Dedicated to his job and proud to be a police officer, brave and courageous. A friend to everyone who knew him.
"He will be deeply missed. We love him so much.
"His friends and family are shocked and devastated by his loss and ask that they are left to grieve alone in peace."
In all, people of 11 nationalities were caught up in the violence.
The attack was the deadliest in Britain since 2005, when 52 people were killed by Islamist suicide bombers on London's public transport system.