Iraqi forces, backed by aerial and ground support from the international coalition, tribal forces and the local population, have been conducting operations in recent months to destroy underground hideouts used by extremists in remote areas of Anbar province.
Remnant extremists have been using a network of hidden tunnels and caves to evade airstrikes and regroup after having lost much of their territory in Iraq and across the border in Syria.
"Airstrikes have been targeting ISIS hideouts and tunnels in areas surrounding remote cities, including the cities of Heet and al-Qaim and attached villages and boroughs," said Heet local council head Mohammed Muhannad al-Heeti.
The airstrikes are based on intelligence provided by the Anbar Operations Command, al-Jazeera Operations, the 7th Army Division and 29th Brigade.
These joint forces are carrying out continuous patrols deep into the desert to locate ISIS tunnels and submit the data to the Iraqi air force and international coalition, which then target them with airstrikes.
"The destruction of these tunnels aims to prevent the terrorist group from using them as bases to launch terrorist attacks on cities, regroup or store weapons and supplies," he said.
Tribal forces provide intelligence
The tips provided by the tribes and shepherds who report to the security forces on these tunnels also play a key role in clamping down on ISIS's remnants in Anbar's desert.
Tribal Mobilisation Forces, which comprise tribesmen who hail from all areas of Anbar, are the most familiar with the desert and its routes, said Falah al-Qaraghouli, a tribal mobilisation forces commander.
They have reported many of these tunnels and routes to security forces, he told Diyaruna.
There is also close co-operation with the shepherds in the desert, who provide "very precise" information and report any suspicious movement deep in the desert, he said.
"Most of [these tunnels] are located in areas adjacent to the international highway, from the border areas to the outskirts of the cities of Ramadi and Fallujah, and areas south-west of the city of Heet," he said.
The Tribal Mobilisation Forces command works with the shepherds in utmost confidentiality and is keen to protect their identities from ISIS elements, said al-Qaraghouli.
Combined ground, aerial surveillance
In addition to tips provided by ground forces and sources, Iraqi forces also rely on drones to survey the desert, locate ISIS tunnels and detect militants' activity, security expert Saeed al-Jayashi told Diyaruna.
Enforcing security in the desert is achieved through striking ISIS sites and curtailing its elements' movements without the need for a constant presence of security forces on the ground, he said.
"Upon receiving information from aerial surveillance or sources on the ground, Iraqi forces act on these tips to block any suspicious activity," he said.
This strategy of combined ground pursuit and aerial surveillance is also being implemented in areas east of Tikrit, in the Hamreen mountain range and around Balad Ruz, which have recently witnessed an uptick in ISIS activity.
The Iraqi military gains achieved against ISIS have deprived it of territory and forced its remnants to move between tunnels, caves and remote valleys in the hope of once again regrouping, al-Jayashi said.
"Security agencies are determined to eliminate all presence of the terrorist group, and to not give it the opportunity to catch its breath," he said.