New York:US Air Force Secretary Deborah Lee James has praised the Indian Air Force (IAF) for the "magnificent execution" of 'Operation Sankat Mochan' which evacuated Indian civilians trapped in South Sudan last month. James, who is scheduled to visit India, told reporters here on Wednesday that she was "looking forward to congratulating the IAF chief in particular on what I think is a magnificent execution of the C-17 operation where you were able to evacuate Indian citizens from South Sudan. Well done on that." Operation Sankat Mochan, which brought back 156 civilians from South Sudan capital Juba, used C-17 Globemaster aircraft purchased from the US. During her New Delhi visit, she is slated to meet Air Chief Marshal Arup Raha, the Chief of Air Staff and Chairman of Chiefs of Staff Committee. She described the IAF as "a very effective fighting unit" and recalled its participation in Red Flag exercises with the US Air Force. During the exercise, she said, "we get together with coalition partners and we train together and interoperate together and we go up sometimes against simulated threats so that we test ourselves on a high-end, very challenging, difficult environment." Most recently the IAF took part in a four-week Red Flag exercise in Alaska that concluded in May. India deployed Sukhoi 30-MK and Jaguars fighter jets and IL-78 mid-air refuelling planes.