South Korean foreign minister Kim Sung Hwan called on North Korea on Tuesday to make an "understandable" explanation of two attacks on the South last year, before returning to the six-party talks on the North's denuclearisation.
"(The North's explanations) must be understandable to our people," Kim told a press briefing.
Kim was asked if the South was sticking to its position the North should admit to the two "provocations" and apologise for the attacks before resuming the aid-for-disarmament nuclear talks.
The "provocations" refer to the sinking of a South Korean warship in March in a torpedo attack, which the North says was not its doing, and the artillery shelling of a border island in November.
In a major breakthrough, the South has accepted a North Korean offer made by the North's minister of the people's armed forces to hold high-level military talks to "present views" on the attacks and try to "reduce military tension" on the Korean Peninsula.
The two sides are to hold a preparatory round of military talks before holding the high-level talks.
South Korea has demanded the North apologise for last year's attacks and pledge to prevent any others.
The six-party talks, involving the two Koreas, the United States, China, Japan and Russia, have been in hiatus for nearly two years.