Metropolitan Police commissioner Cressida Dick has praised the "extraordinary" courage of members of the public and emergency services who "ran towards the danger".
She paid tribute to the actions of those caught up in the terror attacks in the London Bridge area on Saturday night, saying she was sure they had helped save lives.
Addressing media outside Scotland Yard, Ms Dick said: "In the early hours of the morning I visited one of the hospitals where the injured are being treated.
"There I heard truly remarkable stories of extraordinarily brave actions by officers on and off duty who were first on the scene.
"I also heard of colleagues from other emergency services and members of the public who ran towards the danger as this incident unfolded.
"Many, many people risked their own safety to help others and to treat those seriously injured and indeed to confront the suspects involved.
"It's clear to me that the courage of those people during and following the attack was extraordinary and I pay tribute to all of them who came to the aid of those in need during this dreadful attack, and I am sure helped to save lives."
Press Association
