Franklin Graham has said he is "terrified" by the number of Muslims prepared to carry out violence.

The son of evangelist Billy Graham acknowledged the "vast majority" of Muslims were peaceful. But he said there were some "little-discussed, but chilling, findings" from Pew Research Centre in December that showed seven per cent of Muslims in America who believed violence against non-Muslims was "sometimes" justified and one per cent said it was "often" justified.

In a lengthy op-ed for USA Today Graham said that meant 100,000 Muslims in the US who could justify suicide bombings.

"That is not to say that 8% would actually strap on an explosives-packed vest, but the fact that so many find it justifiable is scary enough. And the most likely place that terrorist recruiters or Internet propagandists will find American Muslims who'd be willing to kill is among those Muslims who don't see anything wrong with it."

He continued: "Who would knowingly and willingly accept these odds of a peaceful existence in their own family, neighborhood, workplace or church? For example, would you feel safe accepting a job at a "mostly peaceful" company of 100 employees if that meant only eight of them believed a suicide bombing was sometimes or often justified in the name of their religion (or in the name of anything, for that matter)?

"Would you stay at a hotel whose employees were "mostly peaceful"? Would you trust your car to not explode randomly if a company who boasted its workers were mostly peaceful had made it? Imagine a marketing slogan: "Trust us — we're mostly peaceful." And who would fly an airplane full of mostly peaceful passengers?"

He said "hundreds of millions" would reject an extremist violent Islam. But he said "it's the millions who apparently agree...who terrify me".

The leader of the Billy Graham Evangelist Association and the aid-charity Samaritan's Purse has been a long-time critic of Islam. After the 9/11 terrorist attacks he said it was a "very evil and wicked religion". He has also argued America "should stop all immigration of Muslims to the US until this threat with Islam has been settled", a renowned policy of Republican candidate Donald Trump. 

Russell Moore, president of the Ethics and Religious Liberty Commission of the Southern Baptist Convention, has criticised Franklin Graham's approach to Islam and said "presence of our Muslim neighbors doesn't threaten" the gospel. 

"We should be kind to these Muslim neighbors and share the gospel evangelistically with them."