North Korea launched at least one “projectile” from the vicinity of a missile base on Thursday, apparently a drill or test launch that ended with the weapon crashing into the Sea of Japan.

South Korean intelligence believes two short-range missiles were test-launched during the exercise, probably in a bid to increase pressure on the United States in nuclear negotiations.

The official word from South Korea’s Joint Chiefs of Staff (JCS) on Thursday was that North Korea launched an uncertain number of “unidentified projectiles” from the Sino-ri area, where it maintains a base stocked with Nodong medium-range missiles capable of reaching Japan. Subsequent analysis of the flight path suggested the rogue state may have fired the weapons from mobile launchers some distance from the base.

“Our military has strengthened surveillance and vigilance in case of a further launch from North Korea, and has maintained a full-fledged posture in close coordination with the United States,” the JCS said in a statement.

The Japanese Defense Ministry stated that none of North Korea’s projectiles fell within Japan’s exclusive economic zone and they posed no threat to Japanese security.

Some analysts believe North Korea is testing a new short-range ground-launched ballistic missile, a possible violation of U.N. Security Council resolutions depending on its capabilities.

North Korean state media simultaneously played up this week’s missile launches as ominous portents that Pyongyang’s nuclear missile program is back on track and dismissed South Korean concerns about the launches as a “cock and bull” story.

North Korea’s Rodong Sinmun on Wednesday celebrated North Korea’s “historic” drive for intercontinental nuclear missiles, celebrating the regime in Pyongyang as an “invincible power that has fulfilled the historic cause of parallel development” of its military power an civilian economy while “taking the initiative in policy trends towards peace amid a death-defying confrontation with hostile forces.”

Rodong Sinmun claimed North Korea’s “independent dignity and strategic status have reached a zenith over the past three years.”

“We now have a self-sustaining war deterrence with which we can resolutely subdue and smash any kind of tyranny and fanaticism,” the North Korean paper crowed.

Reporting on the Rodong Sinmun editorial, South Korea’s Chosun Ilbo noted it marked a significant shift from dictator Kim Jong-un’s talk of pivoting to focus heavily on civilian economic development last year.

Chosun Ilbo also found the North Korean boasts of dignity, independence, and incredible economic progress difficult to reconcile with the Communist tyranny begging the rest of the world for food as the United Nations warns of impending mass starvation.

North Korea’s KCNA news agency on Thursday insisted the recent missile launches were merely part of a “routine and self-defensive military drill” and ridiculed South Korean concerns that last year’s inter-Korean agreement to cease hostile activities was in jeopardy. A North Korean official further accused Seoul of hypocrisy for criticizing Pyongyang’s military activities after participating in joint drills with the United States.

Most outside observers agree that North Korea is testing weapons and issuing belligerent pronouncements to express its frustration with the state of nuclear negotiations, which have stalled ever since the second summit between Kim Jong-un and President Donald Trump.

The U.S. special representative for North Korea, Stephen Biegun, was arriving in Seoul when North Korea launched its projectiles.

One of Biegun’s priorities is to discuss food aid for North Korea with South Korean officials. South Korean president Moon Jae-in delicately implied during a televised address on Thursday that North Korea’s bellicose behavior might jeopardize the aid shipments.

“The government planned to provide food assistance to North Korea. As North Korea has launched additional missiles, this plan needs to get a consensus from the public. A meeting of the political parties is needed,” Moon said.

“The main thing is for Washington and Pyongyang to return to negotiations as quickly as possible. If the North has something to say, then it has to clarify what it is dissatisfied with,” he added, gently prodding the North Koreans to knock off their short-range missile tantrums.

The Pentagon on Wednesday announced that U.S. efforts to retrieve Korean War dead from North Korea have been suspended due to deteriorating relations with Pyongyang. Defense POW/MIA Accounting Agency (DPAA) spokesman Chuck Prichard noted that North Korean officials have not communicated with his office since the Hanoi summit in February.

“As a result, our efforts to communicate with the Korean People’s Army regarding the possible resumption of joint recovery operations for 2019 has been suspended,” Prichard said. “We have reached the point where we can no longer effectively plan, coordinate, and conduct field operations.”