Muslims condemned the "appalling" Westminster terror attack as they joined Christian and Jewish leaders for a service just metres from the scene.
Sunni Sheikh Khalifa Ezzat, head Imam at the London Central Mosque, and Sheikh Mohammed Al-Hilli, representing Shia Muslims, stood side-by-side with Archbishop of Canterbury Justin Welby.
Chief Rabbi Ephriam Mirvis and Cardinal Vincent Nichols also joined the gathering outside Westminster Abbey.
They led a minute of silence in tribute to the four innocent victims who were killed and the many who were left injured.
Mr Al-Hilli said: "As a member of the Shia Muslim community here in the United Kingdom I would like to express my condolences to the families of the victims of this heinous and appalling attack.
"We utterly condemn this terrorist act."
Mr Ezzat said: "We condemn this act, which killed innocent people, and those criminals, we shouldn't link them with Islam because Islam, and all religion, calls for peace, co-existence and tolerance.
"What those criminals are doing is not from the principles of Islam. They want to divide us.
"We are here together to stand together and to show solidarity, to show co-operation, to face those people and these crimes."
Mr Mirvis said: "Terrorists seek to instil fear and terror into the hearts and minds of millions. They also seek to divide us.
"Londoners are showing right now that we will always stand up with strength to confront terror and we will never be cowed by it."
Mr Welby said people were still "deeply shocked" by the terror attack and paid tribute to the victims, including Pc Keith Palmer.
He hailed "the police who were there and are here today, whose consistent courage and simple observance of duty is an extraordinary example to all of us and one that we admire very greatly".
Cardinal Nichols said: "Yesterday, I received a message from Pope Francis in which he assured this country of his prayers for our future, for our well-being and for our peace."
Additional reporting by the Press Association.