The U.S. has recently raised groundless suspicions that its advanced weapons technologies are being copied by South Korean engineers, multiple military sources here said Friday, indicating the South\'s rising competitiveness in the defense sector is unsettling to western arms exporters. According to the sources, the U.S. Defense Technology Conversion Council (DTCC) has been keeping close tabs on the latest technologies used in weapons and fighter components manufactured by South Korea\'s Agency for Defense Development (ADD) and other defense companies. The DTCC, made up of intelligence and defense department officials, keeps track of possible technology theft or technology leaks overseas. In June, the U.S. alleged South Korean technicians disassembled the Tiger Eye sensors suite in the F-15K fighter without permission, and the two countries formed a joint investigative team for a weeklong probe in September. The Tiger Eye, a key device installed under the F-15K\'s fuselage, consists of navigation systems and targeting pod devices built using U.S. military technology. The contract between Seoul and Washington stipulates that the importer must not meddle with the product. Sources said the U.S. claimed it had obtained sufficient evidence that the Tiger Eye had been disassembled, while South Korea demanded to see evidence. According to the sources, the U.S. declined to present evidence to protect the identity of its agents here. Then on Oct. 31, Defense Acquisition Program Administration (DAPA) in Seoul said the investigation found no evidence of disassembly and that the U.S. tentatively concluded that the South\'s Air Force hadn\'t illegally damaged the equipment. But sources said the U.S. has recently alleged that South Korea has stolen American technology for three pieces of equipment, including a multiple rocket launcher system and an electronic jamming device. Officials at the defense ministry, DAPA and defense companies said reports of the U.S. raising suspicions over other weapons are merely rumors. But multiple sources said the U.S. may be growing wary of improving South Korean technology in electronic warfare and navigation, among other areas. They also said the U.S. appears to be keeping a close eye on South Korea\'s plan to produce its own fighter jets in a project dubbed KF-X. That project will be based on a separate fighter jet acquisition deal, called F-X, in which South Korea will acquire 60 new-generation stealth fighters from overseas. Two U.S. manufacturers, Boeing and Lockheed Martin, are among candidates and Seoul is scheduled to pick the manufacturer next year. Sources explained that the U.S. may be worried that its competition with South Korea in fighter aircraft production would force it to lower prices of jets. One South Korean government official said the ADD should also be careful to not to create unnecessary misunderstanding. \"ADD is a closed organization because it supposedly develops core weapons systems, but whenever it produces a weapon, it goes way overboard with promotion,\" the official said. \"Basically, the organization and corporate practices at ADD have to change so as not to cause further misunderstanding.\"