North Korea warned Saturday it will make South Korea "pay the dearest price" for hurting the dignity of its supreme leadership.

North Korea accused South Korean media of spreading misinformation about the death of leader Kim Jong-il and his funeral, saying it can no longer tolerate what it called Seoul's smear campaign.

The Daily NK, an Internet news outlet specializing in North Korean affairs, has reported that North Korea sent those who did not shed tears during the mourning period for Kim to labor camps for at least six months, citing an unidentified source in the North.

The outlet also reported that the North has ordered its troops to kill those who try to defect during the mourning period and exterminate their family members.

Tens of thousands of North Koreans wept and wailed in streets across Pyongyang during the televised funeral procession of their leader last month, but South Korean media reported tears could have been staged.

"The Lee group, hell-bent on slinging mud with collections of the world's worst invectives, deserves the severest punishment by justice and truth," the North's official Korean Central News Agency said in a commentary, referring to South Korean President Lee Myung-bak.

The commentary also said North Koreans will "force the puppet group to pay the dearest price generation after generation for decrying their single-minded unity, while hurting even the dignity of the supreme leadership."

The latest warning comes as North Korea is stepping up propaganda campaigns to ensure Kim's youngest son, Kim Jong-un, will consolidate power.

(Yonhap News)