A security expert says the Islamic State attack model is changing as the group looks to spread its ideology.

The group has claimed responsibility for a number of attacks in the past week including the bombings of two Coptic churches in Egypt that killed 40, and a truck attack in Stockholm that killed four.

Human Security Centre director Julie Lenarz told Rachel Smalley smaller, lone-wolf style attacks are becoming the new norm.

"What we need to understand is that problem we're dealing with is not just a few individuals that are carrying out the violence, but these people are indebted to the wider culture - an Islamist culture."

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