South Korean President Park Geun-hye delivers a special address to the National Assembly after North Korea’s recent nuclear and missile tests. (Jung Yeon-Je/AFP/Getty Images)

North Korea’s pursuit of a nuclear weapons program “will only hasten its collapse,” South Korean President Park Geun-hye said Tuesday, forgoing her usual caution to warn in uncharacteristically blunt terms that her government will do all it can to punish Pyongyang for its recent provocations.

Talk of the North’s collapse is normally a no-go topic here, because the prospect not only alarms South Koreans but also enrages Kim Jong Un’s irascible regime. But following the North’s nuclear and missile tests this year, Park is taking a markedly more confrontational approach.

“Dear people of South Korea, it’s obvious now that our previous methods and goodwill cannot break Pyongyang’s nuclear will,” she said in a special televised address to the National Assembly. “I believe we should not provide them with unconditional support anymore or succumb to their provocations. We now need to find a fundamental solution to effectively change North Korea, and it is our time to be brave.”

Her tough words come at a time when South Korea, Japan and the United States are in unusual accord on how to deal with North Korea. Her address also coincides with a buildup in U.S. military muscle on the Korean Peninsula. Four U.S. F-22 stealth fighter jets are set to arrive in the South on Wednesday, while the USS John C. Stennis aircraft carrier is due later in the month ahead of joint military exercises.

Park has pursued what she calls a “trustpolitik” approach to North Korea — trying to build trust without weakening deterrence. But last week, she signaled a significant shift when she ordered the shutdown of the inter-Korean industrial zone at Kaesong on the northern side of the demilitarized zone that separates the two countries.

The Kaesong complex, where about 54,000 North Koreans worked in 124 South Korean-owned factories, had long been kept separate from politics; it was not shuttered even after a North Korean attack on a South Korean naval corvette in 2010 that killed 46 South Korean sailors.

But Park, citing estimates that the South’s government and private enterprises have contributed $3 billion to the North’s government over the past 20 years, including through the Kaesong project, has pulled the plug.

The shutdown was just the start, she said Tuesday. “From now on, the government will start taking stronger and more effective measures to push North Korea to make changes by creating an environment in which the North will realize that nuclear development is not a way to ensure its survival, but a way to ensure the quick collapse of the regime,” she said.

Park’s comments, including the mention of the North’s collapse, took many analysts by surprise.

“She has announced a real change in her policy,” said Choi Kang, vice president of the Asan Institute for Policy Studies, a Seoul think tank. “She didn’t say ‘regime change,’ but it seems that she has something like that in mind.”

There are few economic avenues left for the South to punish the North. The Kumgang tourist area, where South Koreans could visit a North Korean mountain range in a project that generated foreign currency for the Kim regime, was shut down years ago after a South Korean woman was shot by a North Korean guard. Direct sanctions put in place after the 2010 naval attack also curbed economic cooperation and trade.

But there is plenty that South Korea could do militarily, Choi said, including beefing up the capabilities of its armed forces, continuing to blare anti-Kim messages across the DMZ and perhaps even cutting off humanitarian aid.

The South’s recent actions — especially the loudspeaker messages — have infuriated the North. In a statement last week after the Kaesong shutdown, the North’s official Korean Central News Agency labeled Park a “confrontational wicked woman” operating “at the groin of her American boss.”

Pyongyang also has been sending anti-South leaflets over the DMZ with balloons. Some that landed north of Seoul on Tuesday, according to local media, featured a caricature of Park and warned of “divine vengeance” for what it said were her failures, including the 2014 Sewol ferry sinking, in which hundreds died; the high suicide rate; and a MERS outbreak. The leaflet featured death portraits of Park’s mother, who was shot by a North Korean agent, and her father, former president Park Chung-hee, who was assassinated, suggesting that her turn was next.

Separately, Japan has introduced new unilateral economic sanctions against North Korea in response to the tests, banning its citizens from entering Japan and North Korean ships from calling at Japanese ports. Transfers of money also will be restricted.

In Washington, the House and Senate have passed a bill imposing new sanctions against North Korea, and it is now awaiting President Obama’s signature.

But China, the North’s closest ally, has been reluctant to take punitive action that would risk destabilizing its neighbor, a stance that is likely to weaken any measures that the United Nations comes up with.

Yoonjung Seo contributed to this report.

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