The Israeli-made Searcher UAV in service with the South Korean Air Force went down near the city of Pocheon, 25 kilometers (about 15 miles) south of the Demilitarized Zone, which bisects the peninsula, the YTN television said, citing military sources.
No casualties have been reported.
The Searcher has a maximum range of 100 kilometers (over 60 miles) and operates at altitudes of up to 4.5 kilometers (15,000 feet).
The Military Demarcation Line divides the Korean Peninsula into North (the Democratic People's Republic of Korea) and South (the Republic of Korea) near the 38th Parallel following a ceasefire agreement at the end of the 1950-53 Korean War.
The agreement was never followed by a peace treaty, and technically the two Koreas are still at war.
North Korea frequently accuses South Korean and U.S. military of mounting spy flights over its territory.
In August last year, a U.S. Shadow 200 spy drone crashed in an unpopulated area on the South Korean side of the inter-Korean border.
The U.S. has about 30,000 troops deployed on the Korean Peninsula to support South Korea's 680,000-strong force.
