The leaders of North and South Korea will hold a summit in September, their governments announced Monday, as their peace process moves steadily forward despite signs of a growing impasse between Washington and Pyongyang.

The summit will take place in Pyongyang. It will be the third between South Korean President Moon Jae-in and North Korean leader Kim Jong Un this year and only the third time that a South Korean leader has traveled to the North Korean capital for such a meeting.

The Trump administration appears to have run into rougher waters in its attempts in recent weeks to persuade North Korea to denuclearize, but the two Koreas appear to be making more progress in their gradual rapprochement.

The announcement came after North and South Korean government officials held talks on the northern side of the border village of Panmunjom.

In remarks before the talks got underway, Ri Son Gwon, the leader of the North Korean delegation and chairman of the Committee for the Peaceful Reunification of the Country, said he hoped the planned summit would help give “concrete answers” to the problems people are facing.

Afterward, he said a date has been fixed but not announced, “to keep reporters wondering.”

U.S. officials have privately expressed irritation at the breakneck pace of the rapprochement between the North and South amid stalled denuclearization talks with Washington. The United States is pushing nations to tighten the enforcement of existing U.N. sanctions against North Korea, but the opening of dialogue between President Trump and Kim at a summit in June effectively ended Pyongyang’s international isolation.

“It is a different story than U.S.-North Korea, which seems to have become bogged down,” said John Delury, an associate professor at Yonsei University in Seoul. “The two Koreas are more in stride, and the process has ‘taken’ better.”

Seoul is also interested in relaunching plans for a cross-peninsula railway and a joint industrial park, but U.S. officials have told South Korean counterparts that North Korea needs to make more progress on denuclearization before a number of reconciliation projects move forward, said officials familiar with the conversations.

That is not to say that the peace process across the divided Korean Peninsula is smooth sailing. 

On Sunday, a North Korean propaganda website blamed Seoul’s “blind obedience” to U.S.-led sanctions for what it called the failure to make progress since Moon and Kim met on the border in a blaze of publicity in April.

“It’s been more than 100 days since the April 27 Panmunjom Declaration was adopted, but no reasonable fruit or progress has been produced,” the website Uriminzokkiri said. “It is because of America’s sanctions and the South’s unfair participation in them.”

Some South Korean reporters also pointed out a mismatch in the makeup of the two delegations on Monday: North Korea brought officials in charge of railways, land and environmental protection, and economic cooperation to the talks, whereas the South Korean side was made up of officials from the Unification Ministry, national security office and prime minister’s office.

But if that suggested differing priorities, the opening statements as the talks got underway Monday were all about friendship and rapprochement.

“In a realistic sense, this is the major transformation in the ­inter-Korean relationship,” North Korea’s Ri said. “That we are meeting to exchange talks in such a friendly mood like right now signifies that the communication is working.”

In a joint statement afterward, the two sides said they had “reviewed the progress of implementing the Panmunjom Declaration, and discussed further methods to fulfill the Declaration in a sincere manner.”

By contrast, Secretary of State Mike Pompeo seemed to come away empty-handed from a trip to Pyongyang after Trump and Kim’s meeting in Singapore in June, with North Korea blaming what it called the “gangster-like” mind-set of the United States.

Last week, North Korea’s Foreign Ministry also criticized “high-level officials” within the U.S. administration for insisting that the North give up its nuclear weapons before sanctions are eased and for making “desperate attempts at intensifying the international sanctions and pressure.” 

Those officials, the Foreign Ministry said, are “going against the intention of President Trump” to advance relations between the two countries.

While the declaration that followed Trump’s meeting with Kim was widely criticized as being too vague, the Panmunjom Declaration reached between Moon and Kim was much more detailed, Delury said. The two sides also have more experience talking to each other from previous peace processes. 

“The two Koreas match up; they know their counterparts,” he said. “The South Koreans have done this before when they were in government. They are not new to this. When things start to go wrong, they are like, ‘Oh, yeah, we’ve had this before.’ ”

Delury said that was not a criticism of Trump and his team but just to highlight the different problems and contexts of the two parallel peace processes.

A visit by Moon to Pyongyang would be another propaganda coup for North Korea, and there had been talk of arranging it ahead of the Sept. 9 celebration of the 70th anniversary of the foundation of the Democratic People’s Republic of Korea, the North’s official name, when major celebrations are planned.

But Kim Eui-keum, a spokesman for Seoul’s presidential Blue House, told reporters that “early September seems a bit difficult.”

Before the talks, South Korean media reported that Moon may also urge Kim to attend the United Nations General Assembly in New York in late September.

Min Joo Kim reported from Seoul. John Hudson in Washington contributed to this report.