The Washington Post newspaper says U.S. Vice President Dick Cheney reiterated his hard-line stance on North Korea during his week-long tour of northeast Asia.

The paper said a key part of Cheney's agenda during his visit to South Korea, China and Japan has been to warn that negotiations on North Korea's nuclear issue must begin to show results, given the seriousness of the threat posed by North Korea's nuclear programs.

The paper said while each nation officially supports the U.S. administration's position that North Korea's nuclear programs must be eliminated in a complete, verifiable and irreversible manner, there are important differences.

According to the reports, Japan backs the administration's stance but South Korea and China have wavered. China has urged Washington to soften its stance on Pyongyang while Seoul has proposed offering concessions to the communist nation for the nuclear dismantlement.

The paper said U.S. diplomacy on the issue may be further complicated with the new liberal-dominated South Korean legislature more sympathetic to North Korea.