In February, U.S. strikes reportedly killed a large number of Russians working for Wagner Group, a private military company owned by a crony of Russian President Vladimir Putin, after the Russians crossed the Euphrates River deconfliction line and tried to capture a refinery and nearby oil and gas fields by the Syrian city of Deir Ezzor. After the Russians came in contact with U.S. forces at the site, the Americans responded with aircraft and artillery, killing and wounding up to 300 Russians.

Why was Wagner Group there? Because the Russians may have drawn the wrong lessons from the U.S. use of contractors in Iraq and Afghanistan.

Unlike armed U.S. contractors, most of whom provide mobile and fixed security and are equipped with pistols, assault rifles, and machine guns, the Russian contractors were reportedly operating tanks and other armored vehicles. And they were conducting offensive operations, unlike the defensive posture of American security contractors who are guided by Rules for the Use of Force that strictly prescribe when force can be used.

American contractors are prohibited from performing functions that are “inherently governmental,” such as conducting criminal investigations, commanding military forces, or awarding contracts. They are used to free up soldiers for combat duties and to adjust staffing on short notice. Though their deaths usually garner little media attention compared with military casualties, the Pentagon provides a public accounting of their number, tasks, and locations.

After the February strikes the Russians admitted that “several dozen” Russian citizens were killed or injured and that no Russian servicemen were involved. The Director of the CIA, Mike Pompeo, helpfully added that “a couple hundred” Russians died in Syria. So, the Russians communicated that the “red line” was attacking active duty servicemen and that they were sensitive to disclosing the actual number of dead and wounded, which gives the U.S. the outline of a path forward.

After their success in the Donbas region of Ukraine in 2014, the Russians may have thought contractors could also be used in an offensive mission in Syria. But in Syria they were not going up against the ineffective Ukrainian military in a place they considered their backyard. They were operating in the open Syrian desert and near U.S. forces without any attempt at deconfliction.

Russian sources described Wagner’s lunge at the Deir Ezzor refinery as a “dangerous self-initiative” that was not sanctioned by the Russian military command or that the commanders did not want to acknowledge. The move may have been motivated by a deal between Wagner’s owner, Russian oligarch Yevgeny Prigozhin, and the Syrian state oil company that promised him a 25% share in oil and gas production from fields seized from the rebels.

Assuming someone in authority gave Wagner the go-ahead, what are contractors used for? First, to hide the number of casualties. Russian President, Vladimir Putin, declared major combat operations "on the whole accomplished" in March 2016, and most Russian forces redeployed. Though Putin appears to do whatever he wants, he does not ignore public opinion, and no doubt remembers how the flow of bodies from Afghanistan contributed to the collapse of Soviet resolve. Basically, the contractors are part of the Kremlin’s media strategy.

Also, contractors may be used to pursue commercial activities – like seizing oil fields - on the battlefield. In Syria, the Russian military has displayed a “whatever it takes” approach that is oblivious to civilian casualties and infrastructure destruction, but their interests may not include facilitating business opportunities for someone in Moscow so they may ignore the contractor's absent interference with their mission.

The U.S. can take advantage of the Wagner overreach by announcing it will expressly target the contractors when they next engage in combat. This may increase pressure on the Kremlin while avoiding escalation to direct conflict between U.S. and Russian troops. As Moscow has barely acknowledged the presence of the “volunteers,” it won’t have much opportunity for public pushback to future U.S. strikes, though it will seek an opportunity for revenge.

The U.S. can also tell the Syrian government forces it has a particular interest in the contractors, which may make the Syrians reluctant to operate near the Russians, hampering battlefield coordination. And while we’re at it, how about some social media outreach to the contractors asking “Why die far from home for an oligarch?”

And just as the U.S. learned expensive lessons about regulating contractors in the battlefield, now the Russians have too: in February the Russian parliament announced an interest in regulating the use of private military companies, though the project ran into resistance from the siloviki in March, so its fate is uncertain.

Wagner’s murky chain of command (and funding) will give the U.S. the opportunity to paint the group as freebooters and mercenaries and so have a free hand in striking at its units with little worry about direct Russian pushback. The use of the company to secure economic assets for its backers instead of providing defensive security services or training local police and military gives the U.S. and EU an opportunity to apply sanctions if Wagner’s object is plunder and sanctions-busting.

In 2008, responsible governments agreed to the Montreux Document which set out common obligations regarding private military and security companies in war zones. Russia should positively examine the international convention and stop turning the blind eye to the battlefield behavior of its surrogates as America’s Defense Department won’t ignore the opportunity to put the contractors in the crosshairs.

James Durso (@James_Durso) served as a U.S. Navy officer for 20 years specializing in logistics and security assistance. His overseas military postings were in Kuwait and Saudi Arabia, and he served in Iraq as a civilian transport advisor with the Coalition Provisional Authority. He was a professional staff member at the 2005 Defense Base Closure and Realignment Commission and the Commission on Wartime Contracting in Iraq and Afghanistan. He is presently managing director of Corsair LLC, a consulting firm specializing in project management and marketing support in the Middle East and Central Asia.