Washington: The Islamic State poses risks not seen or experienced before, a top aide of President Barack Obama said, underlining that the dreaded militant group has overshadowed al Qaeda as the principal terrorist threat.
"Originally an outgrowth of al Qaeda in Iraq, in the past two years ISIL has eclipsed core al Qaeda as the principal terrorist threat we face. The world has been shocked by the butchery and depravity of these twisted fanatics," said Lisa O Monaco, assistant to the US President for Homeland Security and Counter terrorism.
From their stronghold in Raqqa, Syria, ISIS has displayed an apocalyptic ambition and an unprecedented brutality, she said in an address to the Council on Foreign Relations, a top American think-tank.
"They crucify victims and burn alive others. They enslave women and children, and teach that rape is an expression of God's will. They behead innocents and broadcast their barbarism to the world," she said.
"But it's not only ISIS's unconscionable brutality that troubles us. What keeps me up at night is that this threat is unlike what we've seen before," Monaco said.
Al Qaeda focused on launching catastrophic attacks against the West?the "far enemy".
They used the Internet to post grainy videos and propaganda in PDF form. ISIS is very different.
"A recent report on ISIS was subtitled, From Retweets to Raqqa ? and that, I think, underscores the scale of our challenge. These fanatics are online and on the ground," she said.
They are terrorists, insurgents, and bureaucrats, attempting to control a territory that was at one point larger than the UK. ISIS supporters have shown an ability to engineer high-profile attacks, like blowing up a Russian airliner over the Sinai Peninsula, she added.
"But they also direct foreign fighters to attack soft targets, as they did in Paris. They have deployed crude but deadly chemical weapons, which pose an imminent threat to Syrians and Iraqis. And through their use of social media, ISIL has distributed the threat globally. They can inspire sympathisers and adherents anywhere, turning lost souls into soulless killers?whether in Bangladesh or San Bernardino," Monaco said.