Seismic waves that led to suspicions on a possible nuclear test by the North last week were found to be the result of a blast operation for a waterway project.

The North's Korean Central Broadcasting Station said Monday that the operation was conducted on Friday in a reservoir at Goksan county of Hwanghae Province near the border of the South's Gangwon Province.

The report added that the waterway project is expected to be completed earlier than scheduled thanks to the blasting work.

The North said it began construction for the two-hundred-20 kilometer-long waterway in March.

Signs of seismic waves from the North had raised suspicion that the communist state was preparing for an underground nuclear bomb test.