Foreign Minister Ban Ki-moon has warned North Korea not to use the political crisis in the South as a pretext for delaying six-country talks on its nuclear program.

Ban said in a weekly press briefing that the North Korean nuclear issue and the impeachment are totally unrelated issues.

He said if North Korea takes a half-hearted attitude or does not attend the six-party talks, using the impeachment as an excuse, we cannot help but doubt the North's commitment to peacefully resolving the nuclear issue.

The warning came after inter-Korean economic talks failed to take place as scheduled on Monday after the North, citing "political instability" in the South, demanded a change in the venue.

The meeting was originally scheduled to be held for two days from Monday in Paju, north of Seoul, to discuss ways of settling bilateral trade transactions.

On Sunday, North Korea abruptly proposed that the venue be changed to North Korea's border town of Gaesong. South Korea rejected the North's demand, insisting that the talks be held as scheduled in the South. North Korea did not respond.