SEOUL, Sept. 2 -- A drone from the Democratic People's Republic of Korea (DPRK) flew across the inter-Korean border during S. Korea-DPRK high-level talks, Yonhap News Agency reported on Wednesday citing military sources.

A DPRK unmanned aerial vehicle (UAV) crossed the military demarcation line (MDL) inside the demilitarized zone (DMZ) several times for three days from Aug. 22 when top military officials of the two Koreas held marathon talks in border village of Panmunjom amid the heightened tensions.

After trading artillery fires on Aug. 20, South Korea and the DPRK put their respective troops on the highest alert, bringing the Korean Peninsula to the brink of an armed conflict.

The DPRK drone flew across the border and reached above general outposts in middle and eastern frontline units.

The South Korean military detected the drone with its surveillance radar and scrambled helicopter and fighter jets to intercept the aerial vehicle, yet ending in failure.

A military official was quoted as saying that the type of the drone was not exactly identified as it was invisible to naked eyes. He said that it was not a part of birds as it flew at a constantly low speed and altitude.