Iraq is backing off plans to more than double the number of its US-trained elite counterterrorism forces following heavy losses in the war against the Islamic State (IS).

Originally formed as an elite unit shortly after the US invasion of Iraq, the Counter Terrorism Service faced the brunt of the IS onslaught in Mosul, suffering a 40% casualty rate according to Pentagon estimates. That has led Counter Terrorism Service commanders to reassess efforts to recruit 20,000 troops over the next three years, US Marine Brig. Gen. James Glynn, the deputy commander for special operations in the US-led fight against IS in Iraq and Syria, told reporters at the Pentagon today.

“They’re getting right back to focusing on building their capabilities, and are less concerned with what number they need right now,” Glynn said. Iraq's counterterrorism forces “have a very deliberate plan to get themselves re-fit and refurbished and ready for any emerging threats. This week alone, they have had the opportunity to rotate some folks [out] … and get some well-deserved leave, and begin to focus on their training plan, and some of their equipment updates that need to be provided.”

The US-led effort has trained more than 100,000 Iraqi security forces since the beginning of the anti-IS mission in October 2014. That figure includes 14,800 anti-terrorism troops, an umbrella designation that includes the Counter Terrorism Service unit as well as other elite units, according to coalition figures published last month. A separate report by the Pentagon Inspector General found that 5,000 core Counter Terrorism Service forces have been trained since 2015.