WASHINGTON >> The White House says that despite bellicose rhetoric from North Korea the Obama administration has not seen changes in the regime’s military posture.

White House press secretary Jay Carney said today that the U.S. has not detected any military mobilization or repositioning of forces from Pyongyang to back up the threats from North Korean leader Kim Jong Un.

Pyongyang has reacted angrily to U.S.-South Korean military drills and a new round of U.N. and U.S. sanctions that followed North Korea’s Feb. 12 underground nuclear test.

Carney called the U.S. response “prudent.” He noted that such tough talk from North Korea is part of a familiar pattern.

Carney says the White House takes the threats “very seriously.” But he says the rhetoric “is consistent with past behavior.”

Earlier today, the  U.S. announced its latest conspicuous display of firepower, sending F-22 stealth fighter jets to participate in annual U.S.-South Korean war games that Pyongyang calls preparation for invasion. The new South Korean president, who has a policy meant to re-engage Pyongyang with talks and aid, told her top military leaders Monday (Sunday in Hawaii) to set aside political considerations and respond strongly should North Korea attack.

North Korean leader Kim Jong Un gathered legislators for an annual spring parliamentary session taking place one day after top party officials adopted a statement declaring building nuclear weapons and the economy the nation’s top priorities.

The meeting of the Supreme People’s Assembly follows near-daily threats from Pyongyang, including vows of nuclear strikes on South Korea and the U.S.

Analysts see a full-scale North Korean attack as unlikely and say the threats are more likely efforts to provoke softer policies toward Pyongyang from a new government in Seoul, to win diplomatic talks with Washington and to solidify the young North Korean leader’s military credentials at home.

On Sunday, Kim and top party officials adopted a declaration calling nuclear weapons the “the nation’s life” and an important component of its defense, an asset that wouldn’t be traded even for “billions of dollars.” Pyongyang cites the U.S. military presence in South Korea as a main reason behind its drive to build missiles and atomic weapons. The U.S. has stationed tens of thousands of troops in South Korea since the Korean War ended in a truce in 1953.

North Korea also has threatened in recent days to shut down a jointly run factory complex in the North — the last remaining symbol of inter-Korean rapprochement. But officials in Seoul say hundreds of workers traveled as usual across the heavily armed border to the North Korean factory Monday as they have throughout the rising tensions.

“I have no idea about what it will be like when I go to the North Korean side. It seems OK to be here, but we will be living there in a tense situation for a week,” Kim Won-soo, a South Korean manager working in Kaesong, said before his departure Monday from Paju, South Korea.

While analysts call North Korea’s threats largely brinkmanship, there is some fear that a localized skirmish might escalate. Seoul has vowed to respond harshly should North Korea provoke its military. Naval skirmishes in disputed Yellow Sea waters off the Korean coast have led to bloody battles several times over the years. Attacks blamed on Pyongyang in 2010 killed 50 South Koreans.

South Korea’s new president, Park Geun-hye, is pursuing a policy that seeks to re-engage North Korea with dialogue and aid after five years of standoff. But she told her military Monday to set aside political considerations and respond strongly should North Korea attack.

Under late leader Kim Jong Il, North Korea had typically held a parliamentary meeting once a year. But Kim Jong Un held an unusual second session last September in a sign that he is trying to run the country differently from his father, who died in late 2011.

Parliament sessions, which usually are held to approve personnel changes and budget and fiscal plans, are scrutinized by the outside world for signs of key changes in policy and leadership.

At a session last April, Kim was made first chairman of the powerful National Defense Commission, the body’s top post.

On Sunday, Kim presided over a separate plenary meeting of the Central Committee of the ruling Workers’ Party, which set a “new strategic line” calling for building both a stronger economy and nuclear arsenal.

North Korea’s nuclear weapons are a “treasure of a reunified country” not to be traded for “billions of dollars,” according to a statement issued by state media after the meeting. North Korea’s “nuclear armed forces represent the nation’s life, which can never be abandoned as long as the imperialists and nuclear threats exist on earth.”

Sunday marked the first time for Kim to preside over the committee meeting, a top decision-making body tasked with organizing and guiding the party’s major projects. The last plenary session was held in 2010, according to Seoul’s Unification Ministry, and before that in 1993.

The plenary statement also called for strengthening the moribund economy, which Kim has put an emphasis on in his public statements since taking power. The U.N. says two-thirds of the country’s 24 million people face regular food shortages.

The North also named former Prime Minister Pak Pong Ju as a member of the party central committee’s powerful Political Bureau, a sign that he could again play a key role in the North’s economic policymaking process. Pak reportedly was sacked as premier in 2007 after proposing a wage system seen as too similar to U.S.-style capitalism.

Pak is reform-minded and his promotion sets him up for further advancement and “for him to take the lead in the North’s economic policies,” said Cheong Seong-jang at South Korea’s Sejong Institute.