Muslim leaders have condemned terrorists responsible for beheading a second American journalist, saying: "It is not done in our name."

Imams from across Britain have united in their grief over the deaths of Steven Sotloff, which was confirmed tonight, and fellow American James Foley last month.

A British man operating with the Islamic State (IS) extremists, dubbed Jihadi John, is believed to be behind the killings.

David Cameron is due to chair a meeting of the Government's Cobra emergency committee on Wednesday, while religious leaders from several faiths are due to come together and hold a vigil in Westminster Abbey.

Sayed Razawi, an Imam from south London, said the killings were a perversion of their faith.

He said: "The first reaction on hearing the news for many of us was shock and horror. It shouldn't surprise us because of what IS has done in the past.

"But it is very shocking when someone like IS carries out such barbaric actions in your name.

"I have been in contact with Imams tonight and they are all saying 'this isn't in our name' - it is not Islam."

Mr Razawi, who is joint secretary of the Majlis-e-Ulama - the Ulama Council in Europe that represents the majority of Shia Muslims in the United Kingdom and Europe - said he hoped the majority of people would realise that IS did not represent the Muslim faith.

He said: "We have been condemning IS from the beginning.

"Those who are joining them from the UK generally do not come to mosque, they're in fringe groups so they do not always get into the mainstream.

"If anyone is getting 'inspiration' from IS then we would strongly urge them to get in touch with their Imam and go back to the source of Islam.

"Any atrocity like this (the beheading) is wrong and should not happen."

Dr Shuja Shafi, secretary general of the Muslim Council of Britain, said: "This depraved act is yet another illustration of how this group betrays the very principles of Islam they claim to uphold. They dishonour our faith, and sully the Islamic principles of justice.

"We send our condolences to the family of Steven Sotloff and all those left bereaved by this conflict."