Almost two months after Iraqi forces liberated Ramadi from the Islamic State (IS) terror group, much of the city is in ruins. But the structures that still stand pose a deadly threat from an estimated tens of thousands of improvised explosive devices (IEDs), rigged to blow with the opening of a door or a single footstep.
U.S. military officials describe it as IS's scorched-earth tactics, but it also shows the ease with which the terror group has been able to procure the necessary components to make its signature explosives.
"It just confirms how much they are integrated into local economies and how they can source things either within Iraq or Syria, or abroad," said James Bevan, director of Conflict Armament Research.
Researchers with Conflict Armament Research (CAR) spent 20 months on IS's northern and eastern fronts, studying the flow of hundreds of critical components for the manufacture of IEDs. They found a supply chain encompassing more than 50 companies from 20 countries. Some components came from as far away as Brazil, Japan and even the United States.
Iraqi security forces and civilians gather at the site of a car bomb attack in Baghdad, Oct. 21, 2014.
According to the CAR report released Thursday, in some cases, critical parts went from their manufacturers to IS in as little as one month.
Legal links, local distributors
But the report also said a large part of the supply chain is legal, with parts bound — at least initially — for distributors outside Syria and Iraq.
For example, most of the Islamic State IED detonators, detonating cords and safety fuses — all of which can be used commercially in mining and oil operations — came from seven Indian companies.
"All components documented by CAR were legally exported under government-issued licenses from India to entities in Lebanon and Turkey," the report found.
A type of mobile phone popular with IS fighters in Iraq for making remote-controlled IEDs, Nokia's Model 105 Type RM-908, also arrived in the group's hands indirectly.
The CAR report found that of 10 such phones captured from IS fighters, eight had first been supplied to intermediaries in the United Arab Emirates. The other two, the report said, were sent to distributors in Irbil, a city in Iraqi Kurdistan.
"A lot of their IED components in particular, but also other commodities that they need, are sourced very locally, which makes it more difficult if you want to curtail their operations by imposing international sanctions on them," said CAR's Bevan.
FILE - A burned out car lies amid damaged buildings in Ramadi, 70 miles (115 kilometers) west of Baghdad, Iraq, Jan. 2, 2016. Islamic militants were blamed for the attack.
"It's these small distributors that appear to be the weakest chain," he added.
Some of the distributors may not even been aware that they are selling to IS.
"[Islamic State] may well have smaller agents working on their behalf which are acquiring things, for example, over the border with Turkey and then trucking them across with other commerce," Bevan said.
For months, U.S. officials have been calling on Turkey to clamp down on the border to stem the flow of both goods and foreign fighters to IS in Syria. And while officials in Washington say there has been some improvement, the CAR researchers say Turkey continues to be the pivotal "choke point" for components needed to make Islamic State IEDs.
"The commerce has been a big problem," said Jonathan Schanzer, vice president for Research at the Foundation for Defense of Democracies. "Broadly speaking, there hasn't been enough of a focus on the way goods and services move."
Schanzer, a former U.S. Treasury terrorism finance analyst, said finding ways to crack down is further complicated by the fractured situation on the ground, where pockets of IS-controlled territory may be nestled among areas under the control of the government or other groups.
But a bigger problem may be motivation.
"It ultimately comes down to will,” Schanzer said. “And I believe you have a conflict right now that has offered a lot of people a way to cash in, so there's not a lot of will there."
Still, U.S. officials continue to voice optimism.
"The signs of strain are starting to show themselves," a U.S. official told VOA on the condition of anonymity.
FILE - Turkish soldiers watch smoke billow from the Syrian town of Kobani following the attacks by IS militants as seen from the Turkish side of the border in Suruc, June 25, 2015.
"We see indications that our efforts to disrupt ISIL's sources of revenue are bearing fruit, both because of targeted airstrikes against ISIL's financial and commercial activities and due to our efforts to decrease liquidity into ISIL-controlled territory," Assistant Secretary for Terrorist Financing Daniel Glaser told an audience in London earlier this month.
ISIL is an acronym for Islamic State.
Earlier this month, the U.S. Treasury sanctioned Faysal Ahmad Ali al-Zahrani, believed to be a key player in the IS's oil operations.
Military officials say airstrikes have also degraded the group's ability to profit from the sale of oil and gas. Other airstrikes are thought to have destroyed hundreds of millions of dollars that had been in IS's possession.
Still, there is a lingering concern that such efforts will not be enough to stop IS, which has shown an ability to improvise and innovate both on and off the battlefield. Its manipulation of the IED supply chain is just one example.
"We've yet to come across a group like IS both in terms of the territory it controls and also the degree in which it's tapped into the market within its territory," CAR's Bevan said. "There isn't a comparable group in our experience."