SEOUL, South Korea — Only two years ago the leaders of North and South Korea shared drinks, laughs and vows for peace during three highly orchestrated summits that lowered fears of war that had risen as Pyongyang pursued an arsenal of nuclear missiles. 

That's all gone, for now, and it ended this week with a bang.

The North on Tuesday blew up an empty office building that had allowed the two Koreas to talk in person in the North Korean border town of Kaesong. Pyongyang also said it was scrapping a key military agreement aimed at reducing conventional threats along the border. 

The largely symbolic, made-for-TV explosion has shattered already fading hopes in South Korea that the basic foundation of cooperation with its rival could be salvaged. It's also stoked public fear that the Korean Peninsula will once again take its place as a global hotspot. 

While North Korea's actions may appear abrupt and reckless, the leadership in Pyongyang may be executing a carefully measured plan aimed at winning outside concessions while showing its people a strong face in dealing with its rival. 

It's a pattern that has repeated over the decades. When Washington doesn't give the North what it wants, Pyongyang dials up pressure on the South. 

The North may be betting that Seoul can be drawn back into dialogue, despite the demolished building and hurt feelings, because of liberal South Korean President Moon Jae-in's passion for engagement. 

For now, the North seems focused on elevating tensions in phases. 

It has declared its intention to send troops to now-shuttered North-South cooperation sites in Kaesong and at the Diamond Mountain resort, and to reinstall guard posts and resume military exercises in front-line areas. That would nullify a bilateral military agreement reached in 2018 that established border buffers and no-fly zones and would increase the risk of clashes. 

The public face of the North's recent bashing of the South is Kim Yo Jong, the powerful sister of leader Kim Jong Un, who has been confirmed as his top official on inter-Korean affairs. 

Once all smiles during meetings with South Korean officials on a rare visit to Seoul, Kim Yo Jong now calls South Korea an "enemy" and has given vent to outbursts over Seoul's failure to stop activists from floating anti-Pyongyang leaflets across the border. 

Although North Korea is sensitive to those leaflets' criticism, it's unlikely the country is rupturing relations with Seoul merely over something that has gone on for years. 

Instead, the goal appears to be regaining the world's attention — and especially Washington's — in a bid for much-needed aid and boosting a populace worried about economic hardship.

The North's calculated belligerence comes during long-stalled nuclear negotiations with President Donald Trump's administration that have faltered over disagreements on exchanging sanctions relief for disarmament steps. It also comes as the coronavirus pandemic likely further batters the already broken North Korean economy. 

The North could be deliberately censuring the South to build internal unity and shift public attention away from diplomatic failures and economic shortcomings. 

Entering the last year of an ambitious five-year national development plan, Kim Jong Un in December declared a "frontal breakthrough" against sanctions while urging his nation to stay resilient in a struggle for economic self-reliance.

But experts say the COVID-19 crisis likely thwarted some of Kim's major economic goals by forcing the country into a self-imposed lockdown that shut the border with major donor China and potentially hampered his ability to mobilize people for labor. 

The economic setbacks have left Kim with nothing to show for his high-stakes summitry with Trump. The diplomacy began to implode last year in Vietnam, after their second meeting, when the Americans rejected North Korea's demands for major sanctions relief in exchange for a partial surrender of its nuclear capabilities. 

It's impossible for a North Korean leader to admit to his people that he may have got things wrong. It's far easier to transfer the blame to a scapegoat like South Korea, which assumed the mediator role in negotiations between Washington and Pyongyang. 

In her latest statement against the South on Wednesday, Kim Yo Jong accused Moon of betraying the summit agreements he reached with her brother by accepting the "coercion of his master," a reference to Washington. 

North Korea for months expressed frustration over Seoul's inability to help extract concessions from the U.S. on its behalf and urged its rival to defy sanctions to restart inter-Korean economic cooperation.

Next, the North will likely continue to raise tensions, possibly resuming artillery exercises and other drills in border areas and deliberately having vessels cross the disputed western sea border between the Koreas. 

Those disputed waters have seen past bloody skirmishes, including a 2010 attack on a South Korean naval ship that killed 46 sailors. The North does not recognize the western maritime border drawn unilaterally by the U.N. at the close of the 1950-53 Korean War.

Some think the North could be pressuring the South now in a bid to increase its bargaining power before an eventual return to negotiations with the U.S. after the November presidential election. They say the North likely doesn't want to make any major concessions now when there is a chance U.S. leadership could change.

It's a gamble, though, and North Korea may never get as favorable a political situation as it has now to strike a deal.

Trump, who has taken an engagement approach with North Korea unlike any other U.S. president, is not guaranteed victory in November. And while Moon favors engagement, after decades of bloodshed and animosity, many South Koreans are deeply wary of their northern neighbor.

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By KIM TONG-HYUNG Associated Press

Associated Press writer Kim Tong-hyung has covered the Koreas since 2014.