Two Chinese Su-30 fighter jets intercepted a US Air Force radiation detection plane over the East China Sea in international airspace on Wednesday according to a US official. <br/><br/>The US, today, deemed the incident unprofessional and is addressing its concerns to China about the incident through diplomatic and military channels. Lieutenant Colonel Lori Hodge, a spokesperson for the U.S Air Force's Pacific Air Forces in a statement said, the WC-135 was operating in accordance with international law. <br/><br/>She said, even one of the Chinese fighters executed an inverted maneuver above the American plane, essentially conducting a barrel roll above the plane.<br/><br/>According to media reports, the WC-135 aircraft, Known as Constant Phoenix, sniffs for radioactive isotopes in the atmosphere of a nuclear test. It is deployed to Northeast Asia in advance of possible North Korean underground nuclear tests.