North Korea has nearly completed a fresh investigation it promised Japan last year into the fates of Japanese citizens allegedly abducted by the country decades ago, according to a senior North Korean diplomat.

"What is obvious is that (North Korea) has conducted the investigation in good faith," Song Il Ho, North Korea's top negotiator in talks with Japan, said in an interview Wednesday. "If we decide to do so, we can unilaterally announce the results of the probe as early as tomorrow."

Nevertheless, Song said North Korea has yet to "officially" convey to Japan through diplomatic channels its readiness to deliver the results of the probe.