The defector, identified as Jon Yong Chol during a news conference in Pyongyang Friday, was said to have been paid by the South Korean government to enter the North and blow up a statue of Kim, The New York Times reported.
"Destroying a statue is the most hideous insult to our supreme authority and our people and is an act of war no less serous than an armed invasion," the North's official Korean Central News Agency said Friday.
South Korea confirmed that Jon defected to the South in 2010, but denied that it paid the man to destroy the statue.
"It's completely false," said Kim Hyung-suk, a South Korean government spokesman. "This is propaganda not worth responding to."