There are growing indications that the Islamic State (IS) group is re-organising in Iraq, two years after losing the last of its territory in the country.
Kurdish and Western intelligence officials have told the BBC that the IS presence in Iraq is a sophisticated insurgency, and IS attacks are increasing.
The militants are now more skilled and more dangerous than al-Qaeda, according to Lahur Talabany, a top Kurdish counter-terrorism official.
"They have better techniques, better tactics and a lot more money at their disposal," he said. "They are able to buy vehicles, weapons, food supplies and equipment. Technologically they're more savvy. It's more difficult to flush them out. So, they are like al-Qaeda on steroids."
The veteran intelligence chief delivered his stark assessment in a London accent - the legacy of years in the UK after his family had to flee from the regime of Saddam Hussein.
At his base in Sulaimaniya, nestled in the hills of the Kurdistan region of Northern Iraq, he painted a picture of an organisation that has spent the past 12 months rebuilding from the ruins of the caliphate.
"We see the activities are increasing now, and we think the rebuilding phase is over," said Mr Talabany, who heads the Zanyari Agency, one of two intelligence agencies in Iraqi Kurdistan.
A different kind of IS has emerged, he says, which no longer wants to control any territory to avoid being a target. Instead - like their predecessors in al-Qaeda before them - the extremists have gone underground, in Iraq's Hamrin Mountains.
"This is the hub for ISIS [Islamic State group] right now," said Mr Talabany. "It's a long range of mountains, and very difficult for the Iraqi army to control. There are a lot of hide-outs and caves."
He warned that IS would be nourished by the current unrest in the Iraqi capital, Baghdad, and would exploit the sense of alienation among their fellow Sunni Muslims - a minority community. In Iraq, this is a familiar and bloody pattern.
"If we have political unrest," he said, "this is Heaven or Christmas come early for ISIS."