Upon entering dialogue with the US on denuclearization earlier this year, North Korea has repeatedly expressed frustration over lackluster progress in inter-Korean economic cooperation, due to Seoul’s efforts to uphold layers of international sanctions against Pyongyang.

The two Koreas agreed to “promote balanced economic growth and co-prosperity” through joint projects in the Panmunjom Declaration adopted by South Korean President Moon Jae-in and North Korean leader Kim Jong-un in April. They also agreed to work toward the complete denuclearization of the Korean Peninsula and cease all hostile acts against each other.

Joint inspection on reconnecting and modernizing cross-border roads and railways are being carried out to lay a foundation for future economic cooperation, but Seoul has been cautious.

The US seems adamant about keeping sanctions intact until the North completely abandons its nuclear program. It recently announced additional sanctions against Russian ships and business entities for doing business with North Korea.

“The US has announced additional sanctions against foreign corporations with the excuse that they were conducting ‘unlawful’ business with us,” the Rodong Sinmun added.

“Any acts by anti-unification forces at home and abroad aimed at preventing the implementation of the Panmunjom Declaration will be met with punishment and condemnation from our people.”

North Korea has yet to release any reports on US President Donald Trump’s recent decision to abruptly “postpone” Secretary of State Mike Pompeo’s trip to the North.

Experts saw Pompeo’s proposed North Korea trip as a sign that Washington and Pyongyang were taking further steps toward denuclearization.

Instead, Washington hinted its frustration over the lackluster progress of that process, with US Defense Secretary Jim Mattis saying during a Pentagon briefing on Wednesday that the US had suspended several of its largest military exercises as a measure of good faith, but had “no plans at this time to suspend anymore.”

Meanwhile, both Koreas are still discussing when to officially launch their joint liaison office, the South’s Ministry of Unification said Wednesday. The office was initially scheduled to open by the end of August, but Cheong Wa Dae hinted earlier in the week that the launch could be delayed over the lack of progress in US-North Korea talks, mentioning Pompeo’s canceled Pyongyang trip.

“We have been making preparations to open (the office) within August. ... Consultations are underway related to the schedule for its launch,” Baik Tae-hyun, a Unification Ministry spokesman, told reporters during a regular press briefing.

US officials have reportedly expressed concerns that Seoul’s supply of energy, materials and equipment to the office, situated in the North’s border town of Kaesong, could be considered a violation of sanctions.

However, Joseph Yun, a former US special representative for North Korea policy, said in an interview with Voice of America on Wednesday that he did not view opening a liaison office as a violation of sanctions, noting that there are several diplomatic missions currently in the North Korean capital, including those of Britain, Sweden, Germany and Indonesia.

The Blue House had earlier used the same argument in saying that a liaison office in Kaesong would not be in violation of sanctions.

President Moon is set to visit Pyongyang in September for a third summit with Kim Jong-un, but a specific date has yet to be announced.

By Jung Min-kyung (mkjung@heraldcorp.com)