The United States has demanded that South Korea accept a six-fold increase in the purchase price of F-15K’s night censors, citing discontinued production, a senior defense ministry official said Thursday.

The South Korean Air Force currently operates 60 F-15K Slam Eagles acquired from U.S. aerospace contractor Boeing through two deals in 2002 and 2008. It received the last jet in 2012.

Lockheed Martin installed 10 Tiger Eye sensor suites in the first batch of 10 jets in 2009 to help them fly at a low altitude in order to avoid radar detection and launch precision attacks at night and in bad weather. They consist of navigation systems and targeting pod devices. (Yonhap)