The Associated Press

Source: Paul D. Shinkman, Senior National Security Writer

North Korea on Thursday blasted new, smaller-scale U.S.-South Korea military exercises as an “open challenge” to the aspiration of Pyongyang, seemingly rejecting what had been a key compromise President Donald Trump made following a summit with North Korean leader Kim Jong Un last month.

The fiery rhetoric followed numerous reports this week that North Korea has begun new activity to bolster its nuclear weapons program, despite White House assurances following the high profile February meeting in Vietnam that Kim was committed to denuclearization.

“The ill-boding moves of the south Korean military authorities and the U.S. are a wanton violation of the DPRK-U.S. joint statement and the north-south declarations in which the removal of hostility and tensions were committed to,” North Korean state news service KCNA wrote, using its preferred acronym for itself. The statement described the new downsized exercises as “an open challenge to the aspiration and desire of all Koreans and the international community for peace and stability on the Korean Peninsula.”

The statement represents a troubling escalation following South Korean media reports of new activity at a North Korean intercontinental ballistic missile plant in recent days, the same site Trump has said he would be disappointed to see rebuilt. Senior officials at the South Korean National Intelligence Service reported the movement of cargo vehicles around the Sanumdong factory in Pyongyang, according to the JoongAng Ilbo and Donga Ilbo newspapers.

Cartoons on North Korea

NBC News, citing new details from the Center for Strategic and International Studies, reported earlier this week that North Korea was rapidly rebuilding its Sohae Satellite Launch facility and showed activity that is “consistent with preparations for a test.” The site houses the technology that, if successful, could launch a missile capable of reaching the U.S.

When asked about the NBC report on Wednesday, Trump said he would “be very disappointed if that were happening,” and falsely claimed that the White House had already released information about the new activity at the missile sites.

“I would be very, very disappointed in Chairman Kim and I don’t think I will be, but we’ll see what happens. We’ll take a look. It’ll ultimately get solved,” Trump said.

While some applaud the increased dialogue between the U.S. and the notoriously isolated kingdom, Trump has come under criticism for organizing such a high profile summit with Kim without a clear mandate for what they could accomplish, and ultimately walking away from it prematurely and without an agreement. North Korea watchers fear the publicity gave further legitimacy to the Kim regime – considered the principle reason why the young hermetic leader has pushed for the development of functional nuclear weapons during his rule.

Trump’s decision to scale back military exercises with South Korea – or “war games” as both he and Kim call them – such as the high profile Foal Eagle drills that involve upwards of 10,000 sea, air and ground-based troops, essentially adopted a Chinese suggestion known as “freeze for freeze,” in which the U.S. would reduce its high-profile training operations with Seoul in exchange for North Korean denuclearization. While the exercises are designed to prepare the U.S.-South Korean alliance for the case of actual conflict, some experts say downsizing them will damage relations between the two countries over concerns Trump is prioritizing relations with Kim over South Korean security.

Then-U.S. Ambassador to the U.N. Nikki Haley ridiculed the proposal last year as “insulting,” saying at an emergency Security Council meeting, “When a rogue regime has a nuclear weapon and an [intercontinental ballistic missile] pointed at you, you do not take steps to lower your guard.”