Inter-Korean economic talks, originally set for this week, may not take place as scheduled.

North Korea has refused to attend preparatory contacts with South Korea as of Monday, one day before the scheduled meeting.

The two sides had earlier agreed to hold the 10th inter-Korean Economic Cooperation Promotion Committee Meeting from Tuesday through Friday in Seoul. Delegates were to discuss ways to boost ongoing joint venture projects, including the construction of the Gaesong industrial park.

A South Korean Unification Ministry official said Seoul has proposed twice to the North a preliminary contact to discuss the schedule for the economic talks, but Pyongyang has failed to respond, citing the absence of instructions from above.

Yonhap news agency in Seoul said the North's boycott of the economic talks apparently stems from Pyongyang's anger over an ongoing South Korea-U.S. joint military exercise.