Seoul - North Korea on Monday denounced South Korea's claim that Pyongyang sent a trio of spy drones across the border as a provocative "charade" organised by its "prostitute" president, Park Geun-Hye.
South Korea's Defence Ministry said last week that an investigation into three crashed drones had provided "smoking gun" proof that they were all flown from the North.
In a statement carried by the North's official KCNA news agency, a military spokesperson called the probe findings a "charade for confrontation", and warned the US against being manipulated by its Asian ally and the "disgraceful political prostitute" Park Geun-Hye.
"If Washington pays heed only to what its stooges trumpet, it is bound to be accused of being a senile grandfather trying to stop a child from crying," the unidentified spokesperson said.
The drones were recovered in three different locations in the South near the inter-Korean land-and-sea border between 24 March and 6 April.
One crashed due to an engine problem, while the other two ran out of fuel.
Seoul said recovered data showed they had been pre-programmed to fly over South Korean military installations and then return to the North.
On Monday, Defence Ministry representative Kim Min-Seok reacted angrily to Pyongyang's "absurd" denials.
"It is foolish for North Korea to think it can cover the sky with its palm," Kim told a regular news briefing
Labelling North Korea an abnormal state that exists for the sole pleasure of the ruling Kim dynasty, Kim said it would be best if it "vanished as soon as possible".
The two Koreas have stepped up their rhetoric in recent weeks, amid signs that North Korea is preparing to conduct a fourth nuclear test.
Pyongyang's verbal attacks have become particularly personal, with repeated sexist swipes at President Park and a vicious racist diatribe aimed at US President Barack Obama.