Speaking before a group of U.S. and South Korean businessmen, Rumsfeld said last week that freedom will eventually come and "light up that oppressed land with hope and with promise," casting aside the dictatorship that has ruled the North for more than half a century.
North Korea, whose media regularly churn out anti-American vituperations, is especially thin-skinned when outsiders attack its political leadership.
KCNA, North Korea's official news agency, said Saturday that Rumsfeld's "outbursts ... can not be construed (other) than a desperate shrill cry of a psychopath on his death bed."
Meanwhile, President Bush and Russian President Vladimir Putin, following two days of talks at Camp David, called on North Korea and on to stop their suspected nuclear weapons programs.
"We strongly urge North Korea to completely and verifiably and irreversibly end its nuclear programs," Mr. Bush said.
KCNA accused Rumsfeld and other "neo-conservatives" in the United States of "wantonly harassing peace and security in different parts of the world and igniting wars."
"He is cursed and hated worldwide for this," KCNA said in North Korea's harshest personal attack on a U.S. official since it called Undersecretary of State John R. Bolton "human scum" in August for calling North Korean leader Kim Jong Il a "tyrannical dictator."
"Rumsfeld, whose political faith is to establish the U.S.-style world order by strength, is known to be a typical stupid man for professing 'neo-conservatism' censured and mocked at worldwide," the KCNA's official English translation said. "He is, therefore, not a guy who the DPRK can deal with."
DPRK stands for the Democratic People's Republic of Korea, which is North Korea's official name.
North Korea admitted Saturday that its people live under economic difficulties. North Korea has depended on outside aid to feed its hunger-stricken 22 million people since flood, drought and other bad weather devastated its already inefficient, centrally controlled economy in the mid-1990s. By Pyongyang's own admission, at least 200,000 people died of famine between 1995 and 1998.
"But that is attributable to the economic blockade and sanctions imposed by the U.S. pursuant to its decades-long hostile policy toward the DPRK," it said. "These difficulties are temporary and there are ways to cross over them."
North Korea is now engaged in an international standoff with the United States and its allies over the North's nuclear weapons programs.
Washington is urging the North to abandon its development of nuclear weapons, while North Korea insists that it will boost its nuclear programs as a "deterrent" unless the United States provide a nonaggression treaty, economic aid and diplomatic ties.
The United States, the two Koreas, Russia, Japan and China met in Beijing last month to defuse the nuclear tensions. But the meeting ended with no proposed date for another round.