"Intolerable" sanctions are the best way to convince North Korea to give up its nuclear ambitions, South Korea's presidential national security adviser said Wednesday, amid threats by the communist country to conduct its third nuclear test.

   "The best way to break a nuclear illusion of North Korea is to increase the degree of consequences from the international community to a level that the North is intolerable any more," Chun Yung-woo told a security forum in Seoul.

   Chun said that the world must be united to force North Korea to face up to the reality and choose between two things: survival or nuclear weapons.

   "No other options should be allowed," he said, adding that Pyongyang's leadership should be forced to learn that it won't get economic assistance from the outside world if it continues to push forward with its nuclear weapons development.

   "North Korea can not simultaneously push for both nuclear ambitions and economic development," Chun said.

   North Korea vowed last week to conduct its third nuclear test in response to the U.N. Security Council tightening sanctions against the North as punishment for its December rocket launch. The country had previously detonated nuclear devices in 2006 and 2009.

   South Korea, the U.S. and other neighbors are urging the North to change its policy of confrontation and not to carry out the threatened nuclear test.

   According to South Korean officials, North Korea is ready to conduct a nuclear test at any time, and the country's Punggye-ri underground test site in the country's north east has completed preparations for the test.

   The South Korean analysis is backed up by the latest satellite images of the test site taken by U.S. Web site 38 North which is run by the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies.

   "North Korea's public pronouncements in reaction to a United Nations Security Council Resolution tightening sanctions against Pyongyang have heightened speculation that a nuclear detonation at the Punggye-ri Nuclear Test Facility is imminent," the U.S. Web site said.

   "The site appears to be at a continued state of readiness that would allow the North to move forward with a test in a few weeks or less, once the leadership in Pyongyang gives the order," it said.

(Yonhap News)