More than 500 British Muslim religious leaders and scholars have issued a fatwa in response to the London bombs.
British Muslims have condemned the London bomb atrocity
The religious decree expresses condolences to the families of the victims of the atrocity and wishes the injured a speedy recovery.
It states Islam condemns the use of violence and the destruction of innocent lives and says suicide bombings are "vehemently prohibited".
The fatwa was issued by the British Muslim Forum (BMF) outside Parliament.
Prayer for peace
More than 50 Muslim religious leaders from around the UK stood together outside the Houses of Parliament to hear the fatwa read out.
Gul Mohammad, secretary general of the BMF, quoted the Koran saying: "Whoever kills a human being ... then it is as though he has killed all mankind; and whoever saves a human life it is as though he had saved all mankind."
He went on: "Islam's position is clear and unequivocal: murder of one soul is the murder of the whole of humanity; he who shows no respect for human life is an enemy of humanity.
"We pray for the defeat of extremism and terrorism in the world.
"We pray for the peace, security and harmony to triumph in multicultural Great Britain."
The BMF is an umbrella group launched in March 2005 with nearly 300 mosques affiliated to it.
The fatwa will be read out in mosques across the country on 22 July.
On Friday, a separate public statement was made by more than 40 Islamic leaders and scholars at a meeting at London's Islamic Cultural Centre, organised by the Muslim Council of Britain (MCB).
That declaration also denounces the suicide bombings.