The closed-door meeting at Panmunjom, where the armistice ending fighting in the Korean War was agreed to in 1953, began early Saturday evening, shortly after a deadline set by North Korea for the South to dismantle loudspeakers broadcasting anti-North Korean propaganda at their border, said an official from South Korea's Unification Ministry.
North Korea had declared that its front-line troops were in full war readiness and prepared to go to battle if Seoul did not back down.
There was no word late Saturday night that the talks had ended. Marathon talks are not unusual for the Koreas, who have had long negotiating sessions in recent years over much less momentous issues.
At the meeting, South Korea's presidential national security director, Kim Kwan-jin, and Unification Minister Hong Yong-pyo sat down with Hwang Pyong So, the top political officer for the Korean People's Army, and Kim Yang Gon, a senior North Korean official responsible for South Korean affairs.
Hwang is considered by outside analysts to be North Korea's second most important official after supreme leader Kim Jong Un.
The meeting came as a series of incidents raised fears that the conflict could spiral out of control, starting with a land mine attack, allegedly by the North, that maimed two South Korean soldiers and the South's resumption of anti-Pyongyang propaganda broadcasts.
An official from South Korea's Defense Ministry, who didn't want to be named because of office rules, said that the South would continue with the anti-Pyongyang broadcasts during the meeting and would make a decision on whether to halt them depending on the result of the talks.
While the meeting offered a way for the rivals to avoid a collision for now, analysts in Seoul wondered whether the countries were standing too far apart to expect a quick agreement that could defuse the conflict.
"South Korea has openly vowed to cut off the vicious cycle of North Korean provocations, so it can't manage to walk off with a weak settlement," said Koh Yu-hwan, a North Korea expert at Dongguk University in Seoul. "The South will also likely demand the North to take responsibility for the land mine attack and apologize, and there isn't much reason to think that Pyongyang would accept that."
Koh, however, said that Saturday's meeting might open the door to more meetings between the rivals to discuss a variety of issues.
South Korea had been using 11 loudspeaker systems along the border for the broadcasts, which included the latest news around the Korean Peninsula and the world, South Korean popular music and programs praising the South's democracy and economic affluence over the North's oppressive government, a senior military official said at a news conference, on condition of anonymity.
Each loudspeaker system has broadcast for more than 10 hours a day in three or four different time slots that were frequently changed for unpredictability, the official said. If North Korea attacks the loudspeakers, the South is ready to strike back at the North Korean units responsible for such attacks, he said.
Authoritarian North Korea, which has also restarted its own propaganda broadcasts, is extremely sensitive to any criticism of its government. Analysts in Seoul also believe the North fears that the South's broadcasts could demoralize its front-line troops and inspire them to defect.
The high-level meeting was first proposed by Pyongyang on Friday afternoon. The rival countries reached an agreement for the meeting Saturday morning after the North accepted the South's demand that Hwang be present at the meeting, South Korea's presidential office said.
Hwang and Kim Yang Gon visited South Korea in October last year during the Asian Games in Incheon, but their meeting with Kim, the South's national security director, and then-Unification Ministry Ryoo Kihl-jae failed to improve ties between the countries.
In Pyongyang, businesses were open as usual Saturday and street stalls selling ice cream were crowded as residents took breaks from the summer sun under parasols. There were no visible signs of increased security measures, though even under normal situations the city is heavily secured and fortified. More than 240 South Koreans entered a jointly run industrial complex in the North Korean border city of Kaesong.
The North's state-run media has strongly ratcheted up its rhetoric, saying the whole nation is bracing for the possibility of an all-out war. Leader Kim Jong Un has been shown repeatedly on TV news broadcasts leading a strategy meeting with the top military brass to review the North's attack plan, and young people are reportedly swarming to recruitment centers to sign up to join the fight.
"We have exercised our self-restraint for decades," the North's Foreign Ministry said in a statement Friday. "Now, no one's talk about self-restraint is helpful to putting the situation under control. The army and people of the DPRK are poised not just to counteract or make any retaliation, but not to rule out all-out war to protect the social system, their own choice, at the risk of their lives."
People were willing to talk about the tension and, as is common in public in North Korea — officially called the Democratic People's Republic of Korea — they voiced support for their government's policies and their leader. They also used phrases like "puppet gangsters" to refer to South Korean authorities — everyday terms in the North, in both state media and conversation.
"I think that the South Korean puppet gangsters should have the clear idea that thousands of our people and soldiers are totally confident in winning at any cost because we have our respected leader with us," said Pyongyang citizen Choe Sin Ae.
It was not clear whether North Korea meant to attack immediately, if at all, but South Korea has vowed to continue the propaganda broadcasts, which it recently restarted following an 11-year stoppage after accusing Pyongyang of planting land mines that maimed two South Korean soldiers earlier this month.
Four U.S. F-16 fighter jets and four F-15k South Korean fighter jets simulated bombings on Saturday, starting on South Korea's eastern coast and moving toward the U.S. base at Osan, near Seoul, officials said.
On Thursday, South Korea's military fired dozens of artillery rounds across the border in response to what Seoul said were North Korean artillery strikes meant to back up a threat to attack the loudspeakers.
Thousands of residents in border towns were told to move to shelters ahead of the Saturday afternoon deadline, while fishermen were banned for the second straight day from entering waters near South Korean islands close to the disputed western sea border with North Korea, officials said.
The North denies responsibility for the land mine attack and says it didn't fire across the border, a claim Seoul says is nonsense.
The standoff comes during annual military exercises between the U.S. and South Korea. North Korea calls the drills a preparation for invasion, although the U.S. and South Korea insist they are defensive in nature.