Police in the UK capital have released some details of the incident.
According to the agency, nine people were injured by a stranger who threw an unknown caustic chemical substance into the crowd of passers-by. Three of them - a woman with two children - were hospitalised, the guards said.
Poisoning received and the first three Londoners who ran to the rescue. A little later they were joined by three police officers. All the victims are transferred into the hands of doctors.
Eyewitnesses noted that the attacker purposefully threw a chemical substance, the nature of which has yet to be identified, at a woman with children. The perpetrator managed to flee the scene. The police are using all ground and even aerial means (helicopter) to catch the perpetrator.
Investigators and criminalists have begun to study the circumstances of the incident.
Earlier it became known that unknown persons set fire to a nine-storey house in the centre of Yekaterinburg, firefighters evacuated 30 people.