The first talks between North and South Korea for 10 months have been extended for an extra day.
North Korea's nuclear plans are stoking concern
The decision was announced after a brief meeting on Wednesday between the two sides, after the talks' scheduled conclusion on Tuesday.
During the first two days, Seoul had been trying to persuade Pyongyang to return to six-party talks on its nuclear weapons programme.
Correspondents say there have been few signs of progress so far.
The talks were called by the North to discuss agricultural aid to alleviate chronic food shortages.
But the BBC's Charles Scanlon in Seoul says South Korea has made clear Pyongyang will have to pay a price for moving ahead in recent months with its nuclear weapons programme.
The North has declared itself a nuclear weapons state, and says it has extracted nuclear fuel to make more bombs.
Seoul's chief negotiator said reconciliation and co-operation would be impossible if the North did not give up its nuclear ambitions.
The two sides have agreed to meet again on Thursday.
Pyongyang has always refused to discuss its nuclear programme directly with the South.
South Korea has pledged a new offer if the North returns to international nuclear talks which have been stalled for nearly a year.
It has given no details, but newspapers in Seoul have speculated about a massive aid package.
The US says it will talk to the North Koreans, but only in the context of the six-party framework which brings together all the regional players.
Talks between the two sides will resume on Thursday.