(AFP) -- Ali al-Bayati, a commander of the Hashed al-Shaabi paramilitary units which fought alongside Iraqi security forces in a gruelling battle against the group, said the Nimrud region of northern Iraq could "fall at any time because security there is fragile".
Last July, the authorities in Baghdad announced with much fanfare the "liberation" of nearby Mosul, Iraq's second city.
Isis fighters who fled their former stronghold and took refuge to the west, in the vast desert towards the Syrian border, have since launched attacks on security forces and civilians, Bayati said.
Hiding out in valleys and gullies as well as trenches dug before their ouster from Mosul, the group has built up stockpiles of arms, fuel, water and food.
More than 4,000 Isis member have been arrested in Nineveh province since Mosul's capture, according to police chief General Wathiq al-Hamdani.
But Aed al-Louayzi of Nineveh's provincial council said several civilians have been robbed or killed inside the city itself, some by assailants disguised as soldiers.
He says the attacks have been the work of Isis members from the areas of Tal Afar and Hatra, both towns also recaptured last year from the terrorists.
Hisham al-Hashemi, a specialist on terrorist movements, said Iraq's announcement in December of military victory "simply means that the (black) Isis flag is no longer flying" over government buildings.
The Hashed, which is patrolling the border with war-torn Syria, says it faces infiltration attempts by terrorists on a daily basis.
Although Isis is also on the verge of overall military defeat in Syria, it surprised observers last week by announcing a comeback in the country's northwest.
In the Hawiyah area of northern Iraq, at least three civilians and a Hashed fighter have been killed this month, according to security sources.
They said around 60 terrorists have also died in fighting around Hawiyah, one of the last Isis urban strongholds retaken by Iraqi forces.
On Monday, a twin suicide bombing in Baghdad cost more than 30 lives, prompting Prime Minister Haider al-Abadi to order security forces to "eliminate Isis sleeper cells" and protect civilians.
But Hashemi said the threat is more immediate.
"This concept of sleeper cells is a mistake. They are not sleepers, they are active," he said. "They are capable of mounting attacks and even of taking control of zones."
(Photo: AFP)