Pyongyang has urged Washington to ease economic punishments, but the US says that can't happen until the North completely denuclearizes.
Cho did not say if North Korea had raised the case of the restaurant workers on Monday, merely saying it had not brought up new issues.
One issue that has angered North Korea recently has been the case of a dozen North Korean restaurant workers who came to the South in 2016 via China.
North Korean leader Kim Jong Un and South Korean President Moon Jae-in met in April and agreed to have another summit in autumn, this time in the North's capital, Pyongyang. Former South Korean President Roh Moo-hyun also met Kim Jong Il in Pyongyang in 2007.
But relations subsequently soured as the North accelerated its pursuit of nuclear weapons and the South elected conservative governments.
The agreement was reached during high-level talks between the two sides at the Panmunjom border village on Monday.
South Korean President Moon Jae-in shakes hands with North Korean leader Kim Jong Un as Kim leaves after a farewell ceremony at the truce village of Panmunjom inside the demilitarized zone separating the two Koreas, South Korea, April 27, 2018.
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In opening remarks, the head of the North Korean delegation set a positive tone for the day's meeting, comparing the current state of inter-Korean relations to very close friends where nothing can stand between the two. Sanctions will remain in place until North Korea takes concrete and verifiable steps toward denuclearisation.
"It would be hard in early September, which means until September 10", Moon's spokesman Kim Eui-kyeom told reporters, citing a "reason all reporters can guess". It would be good for them to meet again, but the planned meeting should not be talks for the sake of talks.
The Kim regime takes issue with the Trump administration's support of global sanctions impacting the country; reaction from Bill Richardson, former USA ambassador to the United Nations. North Korea seemed to point the finger at the South for what it sees as lackluster progress on their joint projects.
The North has maintained that denuclearization is a matter to be discussed mainly with the US, not South Korea.
But an obsession with declaring an end to the war - without any substantial progress in denuclearization - could jeopardize the entire peace process, as the North has not yet taken any substantial denuclearization action, like providing the inventory of its nuclear and missile arsenal.
South Korean officials said the Pyongyang summit would help improve cross-border ties.
The ministry official said that the government plans to report its probe results on the alleged illegal shipments to the UN Security Council's sanctions committee as early as this week, adding the USA has already been briefed on the matter. Cho said he urged North Korea to continue its nuclear negotiations with the U.S.