The South Koreans have been for years trying to purchase the Global Hawk from the US, but the US has continuously put off selling the Global Hawks due to fears of technology being leaked.  It appears now that the US is just going to fly the Global Hawks over South Korea to monitor North Korean activities instead of selling them:

The U.S. is negotiating with South Korea to fly the RQ-4 Global Hawk surveillance drone near the Demilitarized Zone, a move that could provide an unprecedented view of goings-on in reclusive North Korea and draw the ire of China.

Flown extensively in Afghanistan and Iraq for the past 10 years, the first Global Hawk arrived on Guam late last year and there are now three flying in the Asia Pacific theater.

South Korea is among a large group of nations in the region with whom U.S. officials are negotiating for flyover rights, according to Lt. Col. Terran Reneau, chief of intelligence, surveillance and reconnaissance for the 13th Air Force in Hawaii.

Reneau did not give a timetable for the negotiations with the South Koreans but added: “I think we are very close” to flying in Korea. South Korean officials would not comment on the Global Hawk issue.

Lt. Col. David Gerhardt, Pacific Air Forces’ chief of command and control, intelligence, surveillance and reconnaissance requirements, added: “Global Hawk will likely fly over land in Korea as soon as agreements have been solidified to do that.”  [Stars & Stripes]

You can read more at the link, but the Chinese are upset because the Global Hawk has technology that can look all the way into China even though it is flying over South Korea.