South Korea's defence ministry said last week it was convinced that three rudimentary unmanned aerial vehicles (UAV) recovered in recent weeks were of North Korean origin.
Wreckage of the drones was found in three different places, including Baengnyeong island near the rivals' disputed sea border.
The ministry said analysis of the debris had secured various pieces of "circumstantial evidence" that clearly pointed to North Korea.
In its first clear denial, the North's Committee for the Peaceful Reunification of Korea (CPRK) said the South's accusation was baseless.
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"It is a vicious attempt to fabricate a second Cheonan incident," the statement added, referring to the South Korean naval corvette, Cheonan, which sank with the loss of 46 lives in 2010 near the South's disputed Yellow Sea border with the North.
An investigation by a South Korean-led international commission concluded the vessel had been sunk by a torpedo from a North Korean submarine -- a charge Pyongyang has always angrily denied.
An inspection group of the North's powerful National Defence Commission said in a separate statement today that Pyongyang was willing to make "everything clear," denouncing Seoul for fabricating the second and third Cheonan cases.
"It is an inveterate bad habit of the South Korean authorities to cook up shocking cases and kick up anti-DPRK (North Korea) confrontation hysteria by linking those cases with the DPRK whenever they are driven into a crisis," it said.
North Korea "remains unchanged in its stand to jointly investigate all cases including the Cheonan case as they claim the North was involved in them", the NDC inspection group said.