SEOUL, South Korea — North Korea’s parliament on Monday approved the appointment of a new premier seen by outside experts as an economic reformer one day after top party officials adopted a declaration making nuclear arms and a stronger economy the nation’s top priorities.

The U.S., meanwhile, made its latest conspicuous display of firepower, announcing it had sent F-22 stealth fighter jets to participate in annual U.S.-South Korean war games that Pyongyang calls preparation for an 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 to set aside political considerations and respond strongly should North Korea attack.

The reemergence of Pak Pong Ju as premier at an annual spring parliamentary session is seen by analysts as a clear signal that leader Kim Jong Un is moving to back up recent statements vowing to focus on strengthened economic development. The U.N. says two-thirds of the country’s 24 million people face regular food shortages.

Pak served as the North’s premier in 2003-2007, according to Seoul’s Unification Ministry. He was sacked initially because of a proposal for an incentive-based hourly, rather than monthly, wage system deemed too similar to U.S.-style capitalism, Japan’s Mainichi Shimbun newspaper reported in 2007. Pak replaces Choe Yong Rim, who is 82.

“Pak Pong Ju is the face of economic reform, such as it exists — reform with North Korean characteristics as they say,” said John Delury, a professor and North Korea analyst at Seoul’s Yonsei University.

Any economic changes won’t be radical, Delury said, and, for the time being, they’re mostly aspirational. One possible change could entail a shift of part of the country’s massive military spending into the economy as a whole, he said.

Pak is widely known for spearheading reforms in 2002, when the government began allowing some markets, although it later backtracked, said Koh Yu-hwan, a North Korea analyst at Seoul’s Dongguk University. His appointment could be a message to the outside world that North Korea wants to calm tension and focus more on economic revitalization, Koh said.

Pyongyang has reacted with anger to the U.S.-South Korean military drills and to a new round of U.N. and U.S. sanctions that followed its Feb. 12 underground nuclear test, the country’s third. 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.

Despite the rising hostility, recent rhetoric has focused on efforts to turn around a moribund economy and nuclear development.

“There was a danger that this was getting to the point … of a permanent war footing,” Delury said. “In the midst of this tension and militant rhetoric and posturing, Kim Jong Un is saying, ‘Look, we’re still focused on the economy, but we’re doing it with our nuclear deterrent intact.'”

On Sunday, Kim and top party officials adopted a declaration calling nuclear weapons “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 with a truce, not a peace treaty, in 1953.

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.

Under late leader Kim Jong Il, North Korea 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.

At Monday’s session, Kim Kyok Sik, North Korea’s defense minister who is believed to have been responsible for deadly attacks on South Korea in 2010, was appointed to the National Defense Commission. North Korea also named Choe Pu Il, a general in the Korean People’s Army, to the commission.

On Sunday, Kim Jong Un presided over a separate plenary meeting of the Central Committee of the ruling Workers’ Party, a top decision-making body tasked with organizing and guiding the party’s major projects. The meeting set a “new strategic line” calling for building both a stronger economy and nuclear arsenal.

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,” according to a statement issued by state media after the meeting.

Sunday marked the first time for Kim to preside over the committee meeting. The last plenary session was held in 2010, according to Seoul’s Unification Ministry, and before that in 1993.