The inter-Korean liaison office in Gaeseong, North Korea. Korea Times file

By Park Si-soo

North Korea has abruptly withdrawn its officials from an inter-Korean liaison office in Gaeseong, North Korea, South Korea's unification ministry said Friday, in a setback to inter-Korean relations that have been peaceful for more than one year.

The ministry said the North had notified the South during a liaison officers' meeting earlier in the day that it would pull out of the office in accordance with a directive from above and later put the decision into action.

It happened three weeks after the second U.S.-North Korea summit in Vietnam collapsed due to disputes over U.S.-led sanctions on the nuclear-armed North.

The North said it "is pulling out with instructions from the superior authority," according to the ministry. It didn't say whether North Korea's withdrawal of staff would be temporary or permanent.

The North said it "will not mind the South remaining in the office" and that it would notify the South about practical matters later, the ministry said in a statement.

Seoul's Vice Unification Minister Chun Hae-sung told reporters that South Korea plans to continue to staff the liaison office normally and that it expects the North will continue to allow the South Koreans to commute to the office.

He said Seoul plans to staff the office with 25 people on Saturday and Sunday.

The South Korean statement calls the North's decision "regrettable." It said South Korea urges the North to return its staff to the liaison office soon.

The joint liaison office opened in September under an agreement reached at South Korean President Moon Jae-in's first summit with North Korean leader Kim Jong-un in April, 2018.

Cheong Wa Dae held an emergency meeting of its National Security Council (NSC) shortly after the news broke.

Top presidential security adviser Chung Eui-yong presided over the meeting, according to Cheong Wa Dae. The presidential office did not give further details.