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(Image: AP/David Goldman)

Amid the confusion of the sudden collapse of the Afghan government and the restoration of the Taliban, one thing is apparently for certain: there'll be more terrorism.

The US withdrawal and victory for the Taliban will add a "spring to the step of those who are railing against the infidels, the non-Muslim world", ANU professor John Blaxland told the ABC. "The terrorist challenge is exponentially greater than it was two decades ago."

A "counter-terrorism expert", Greg Barton, also told the ABC it would vindicate jihadis everywhere: "In the last two decades, Salafi-jihadi groups around the world have increased three- or four-fold, conservatively."