Is ISIS violence expanding worldwide?

While world leaders have spent the last few months focusing on how to contain ISIS in Iraq and Syria, there are some fears the Sunni jihadist group may be exporting its violent tactics to foreign countries.Australian authorities announced Thursday that they had detained six people after counterterrorism raids foiled a plan inspired by the Islamic State in Iraq and Syria (ISIS) to carry out random beheadings in Sydney and Brisbane.

The thwarted plot has gripped the world, but it may be too early to determine whether it's part of a larger global campaign for ISIS, says Christian Leuprecht, a security expert affiliated with the Royal Military College and Queen's University in Kingston, Ont.

"What we don't know yet about [ISIS] is if it intends to compete with al-Qaeda as the pre-eminent transnational organization, or whether it intends to stick with its current strategy," which is to capture and hold territory in Iraq and Syria, says Leuprecht.

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Even so, there are other indications the group may be operating outside the borders of the caliphate, or Islamic state, that it declared in July.

In May, Saudi authorities arrested 62 suspects in what was thought to be the first ISIS-related cell.

Around the same time, suspected ISIS operatives were picked up in Spain and Germany, says Clinton Watts, a former U.S. soldier and counterterrorism agent who is a senior fellow at the Foreign Policy Research Institute in Philadelphia.

Different from al-Qaeda

Given that ISIS has been around in various incarnations since 2003 – beginning as al-Qaeda in Iraq – Leuprecht says that if the group's objective was to be a global threat like al-Qaeda, "they would have had opportunity by now to mount these types of attacks."

"They have not. This is moderately to modestly reassuring."

While the ISIS threat has been a pressing concern for many governments, in a speech to the Council on Foreign Relations last week, U.S. Secretary of Homeland Security Jeh Johnson said the U.S. has "no credible information that ISIS is planning to attack the homeland of the United States."

If ISIS were inclined to plan foreign attacks, it would likely target regional countries such as Saudi Arabia, Turkey and Jordan first, says Nicholas Heras, a Middle East analyst for both the Jamestown Foundation and the Center for a New American Security.

But experts say even if ISIS isn't planning a co-ordinated attack on foreign targets, that doesn't preclude the possibility that returning ISIS fighters or those simply inspired by the group's message might carry out attacks on its behalf.

Leuprecht says the Canadian security intelligence community is "deeply concerned" about returning jihadis "who may eventually be looking at mounting something like the Boston Marathon bombing."

One of the things that distinguishes ISIS from parent organization al-Qaeda is that the former is probably less concerned strategically about the work of "inspirational wannabes," says Watts.

"Al-Qaeda was always nervous about the inspirational wannabes because they would attack targets of dubious importance, or bumble it," says Watts. "ISIS probably doesn't care."

'Direct exhortations'

ISIS has become notorious for its use of online media to stoke and recruit new members. In addition to videos featuring the beheadings of two U.S. journalists and a British aid worker, the group recently released "Flames of War," a Hollywood-style trailer that promises the fight between ISIS and the West "has just begun."

As more countries have signed up to fight ISIS in the Middle East, the group has taken to social media to spur sympathizers worldwide to carry out foreign attacks on its behalf.

In announcing the foiled beheading plot Thursday, Australian Prime Minister Tony Abbott said senior ISIS members had made "direct exhortations" to "networks of support back in Australia to conduct demonstration killings here in this country."

The group has also responded to U.S. President Barack Obama's pledge to step up airstrikes against ISIS, says Heras. "ISIS has definitely stepped up its rhetoric in the last week."

Heras says that in the face of greater U.S. military action in Iraq and Syria, ISIS has urged followers online to find out information about the families of U.S. military personnel in Iraq and "carry out lone wolf attacks."

"This is a very disturbing development," says Heras, "and very difficult to prevent."