British Prime Minister Theresa May has visited a hospital where she spoke to victims of the terrorist attack near Parliament as well as hospital staff.
About 40 people were injured in the attack, of whom 29 remain in hospital, seven in critical condition. Four people, including the attacker, died.
"She has signed the book of condolence and she has recently returned to Number 10 (Downing Street) after a private visit to a hospital where she spent around 40 minutes speaking with victims of yesterday's events, ward staff, clinical staff ... to thank them for their work," the spokesman told reporters.
May also met Queen Elizabeth on Wednesday evening (UK time) for a regular meeting, he said.
Earlier on Thursday the UK PM had addressed Parliament and confirmed that the attacker, later revealed to be 52-year-old Khalid Masood, was British-born.
"What I can confirm is that the man was British-born and that some years ago he was once investigated by MI5 in relation to concerns about violent extremism," she told MPs in her first House of Commons speech after the attack.
"This was an attack on free people everywhere and on behalf of the British people I would like to thank our friends and allies around the world who have made it clear they stand with us."
May said that by continuing with life as normal, Londoners and Britons were sending a message to the terrorists that they will not win.
"The greatest response lies not in the words of politicians, but in the every day actions of ordinary people. For beyond these walls today, in scenes repeated in towns and cities across the country, millions of people are going about their days and getting on with their lives," she said.
"The streets are as busy as ever, the offices full, the coffee shops and cafes bustling.
"As I speak, millions will be boarding planes and aeroplanes to travel to London and to see for themselves the greatest city on Earth.
"It is in these actions - millions of acts of normality - that we find the best response to terrorism."