The United States is displeased with South Korea's disclosure of information related to its troubled fighter jet development project, multiple sources here said Monday.
  

South Korea has sought the transfer of two dozen technologies from the ally in its $15-billion program, codenamed KF-X, aimed at producing its own fighter jet to replace the aging fleet of F-4s and F-5s.
  

This desire for technology is one of the key reasons for Seoul's decision last week to buy 40 F-35s from Lockheed Martin.
  

But the U.S. has refused to transfer four technologies -- the active electronically scanned radar (AESA), infrared search-and-rescue system (ISRS), electro-optical targeting pod and radio frequency jammer -- according to the Defense Acquisition Procurement Administration.
  

Washington is also reportedly negative about handing over some of the other 21 technologies, including the twin-engine system, requested by Seoul.
  

South Korean media and lawmakers have paid keen attention to the issue, critical of DAPA's handling of it.
  

Under growing public pressure, the DAPA has formally stated that it is continuing consultations with Lockheed over the program. A DAPA delegation visited Washington last week for the negotiations.
  

"The U.S. has complaints about revealing technology items in great detail (to media)," a government source said. "The U.S. side has expressed displeasure with the South Korean government on several occasions, including the talks with DAPA." (Yonhap)