A senior U.S. official called North Korea “the most significant source of instability” in East Asia last week as military tensions continued to rise on the peninsula amid Pyongyang’s hardened rhetoric against South Korea and the U.S.

“I believe the most significant source of instability in the region is North Korea and its reckless pursuit of a larger and larger nuclear program and the missiles to deliver those weapons around the world,” said U.S. Deputy Secretary of State Antony Blinken during a press conference in Japan ― the last leg of his Northeast Asia tour ― on Friday.

“And that’s why we’ve been trying to make common cause with Japan, with South Korea, with China, with Russia to convince North Korea that it needs to denuclearize.”

His remarks came amid a freeze in relations between Washington and Pyongyang, and persistent military threats by the North, which escalated after its recent vow to step up its efforts to develop high-tech weapons.

During a meeting of the politburo of the North’s ruling Workers’ Party last Tuesday, the North adopted a defense policy document in which it vowed to develop “accurate, lightened, unmanned, intelligent military equipment that correspond to the requirements for modern-day warfare.”

Analysts said that this could point to nuclear arms that are small enough to mount on long-range ballistic missiles, or inexpensive yet highly efficient weapons systems such as drones and stealth weapons systems.

Given the North’s vow to develop advanced military equipment, observers predicted that the reclusive state could showcase some of its weapons ― developed or under development ― during major events such as the 70th anniversary celebration of Korea’s liberation from Japan’s colonial rule on Aug. 15 or the 70th anniversary of the foundation of the Workers’ Party on Oct. 10.

Over the weekend, Pyongyang criticized a recent series of military exercises including South Korea-U.S. joint marine drills.

“Should warmongers (in the South) continue to be on a road of military confrontation despite our repeated warnings, it would face merciless punishments,” said a commentary in the Rodong Sinmun, the daily of the Workers’ Party, on Saturday.

“Can the inter-Korean issues be resolved and can the two Koreas realize (the goals of) inter-Korean reconciliation and unity when we sit down for talks with these warmongers? The South should choose between facing a miserable end with the final confrontation with us, and resolving bilateral issues after stopping military provocations.”

Cross-border tensions have remained high amid the continued deadlock in inter-Korean relations. Seoul has pushed for the unconditional resumption of inter-Korean talks, while Pyongyang demanded Seoul lift the so-called May 24 economic sanctions against it.

Pyongyang has also demanded that Seoul and Washington cancel their upcoming annual drills, in return for a moratorium on its nuclear tests. But the allies rejected the proposal, saying the two issues were unrelated.

By Song Sang-ho (sshluck@heraldcorp.com)