South Korea has said that high-level talks with North Korea scheduled to begin in Seoul on Wednesday have been called off.
Kim Hyung-suk, a spokesman for the South's Unification Ministry, told reporters on Tuesday that North Korea had told South Korea that the South's choice for its chief delegate for the talks, the deputy unification minister, was not appropriate.
North Korea had said the South's choice was a "grave provocation", Kim said.
For its part, South Korea had hoped that the North would send a senior ruling Workers' Party secretary known to be a close adviser to North Korean leader Kim Jong-un as an indication that the North was serious about the meeting.
But North Korea sent notice that it would be a relatively unknown bureaucrat who would be leading the delegation, the South Korean ministry spokesman said.
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The spokesman said the North's decision on its delegate was "abnormal" and the person chosen was not fit to be a genuine representative of North Korea's leadership.
"Our government regrets North Korea's position," the South Korean spokesman said.
It was not clear if North Korea was withdrawing its offer of talks altogether but South Korea said it remained open for dialogue when the North was ready.
The two Koreas had agreed on the senior-level talks following marathon negotiations aimed at rebuilding trust between the two amid months of soaring tensions and threats of nuclear war.
The proposed talks were supposed to focus on stalled cooperation projects, including the resumption of operations at a jointly-run factory park near the border in North Korea.
The agreement to hold the talks were announced on Monday.