David Cameron has described the murder of Glasgow shopkeeper Asad Shah as shocking.
The Prime Minister also appealed for groups to work together to combat extremism.
His comments came as he was asked by the SNP’s Westminster leader Angus Robertson to support the United Against Extremism campaign, which aims to foster understanding of the prejudice faced by the Ahmadiyya Muslim community in Scotland.
Mr Shah was fatally stabbed outside his shop in March.
Mr Robertson said that the murder was “just the most recent example of sectarian extremism targeting the Ahmadiyya Muslim community in the UK.
“It is time for all communities and all faith leaders of all religions to stand up against extremism.”
Mr Cameron said that the campaign had his full support.
He added: “This was an absolutely shocking murder and I think what it demonstrates again… is that we need not only to stand up against violence and acts of appalling violence like this.
“But we also need to stand up against the extremist mindset that sometimes tries to justify events like this or other such outrages.”
The Conservative leader also said that faith leaders could play a large role in standing up against extremism.
He added: “The attack on Ahmadiyya Muslims by other Muslims demonstrates once again that what we face is not some clash of civilisations between Islam and Christianity or Islam and Buddhism.
“What we are seeing is a small minority within one of the great religions of our world, Islam, believing that there is only one way, a violent extremist way, of professing their faith.”