North Korea has rejected South Korea's offer to resume high-level talks, citing concerns over recent anti-Pyongyang leaflets sent over the border by South Korean activists.
South Korea had proposed that the high-level dialogue, agreed to earlier this month, be held Thursday at the border village of Panmunjom.
Seoul's Unification Ministry said the North on Wednesday insisted the talks cannot be held as long as the South does not prevent the leaflet drops.
Ministry spokesman Lim Byeong-cheol said it is unfortunate the talks cannot continue, but said Seoul cannot accept what he called "unjustifiable demands."
"Our government once again emphasizes that the launch of balloons containing leaflets cannot be controlled by the government under our system," said Lim.
Seoul officials argue that they cannot legally prevent the demonstrators from exercising their freedom of expression.
North Korea has repeatedly threatened to call off the dialogue because of the leaflets, which are sent over the border in large balloons.
Earlier this month, North Korea opened fire at the balloons, setting off a brief exchange of small arms fire between the two sides. There were no reports of injuries.
It was the latest in a series of clashes, on sea and on land, that threaten to disrupt the talks.