The Obama administration said Monday that it has not seen changes in North Korea’s military posture despite its bellicose rhetoric.

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

Nonetheless, the United States has made a point of publicizing its recent military moves, including the deployment of bombers and F-22 stealth fighters to South Korea as part of two-month-long military exercises.

On Monday, U.S. officials said that a Navy guided-missile destroyer, based in Japan and capable of shooting down ballistic missiles, had been positioned slightly closer to the Korean Peninsula, though still within its usual operating area.

Last month, the Pentagon announced plans to increase, by 2017, the number of Alaska-based missile interceptors designed to shoot down any North Korean missile launched at U.S. territory.

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 underground nuclear test on Feb. 12.

Carney called the U.S. response “prudent.” He noted that tough talk from North Korea is part of a familiar pattern. He said the White House takes the threats “very seriously,” but he said the rhetoric “is consistent with past behavior.”

After weeks of warlike rhetoric, Kim gathered legislators Monday for an annual spring parliamentary session, one day after top party officials adopted a statement declaring the building of nuclear weapons and the economy top priorities.

The parliament approved the appointment of a new premier seen by outside experts as an economic reformer. The re-emergence of Pak Pong Ju, the North’s premier from 2003-2007, is seen by analysts as a clear signal that Kim is moving to back up recent vows to strengthen economic development.

The schedule for the Supreme People’s Assembly in Pyongyang was unclear. Under Kim Jong Il, North Korea had typically held a parliamentary meeting once a year. But his son held an unusual second session in September in a sign that he is trying to run the country differently from his father, who died in late 2011.

The assembly session follows near-daily threats from Pyongyang, including vows of nuclear strikes on South Korea and the United States.

Analysts say that a full-scale North Korean attack is unlikely and that 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 Kim’s military credentials at home.

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 would not 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 United States has stationed thousands of troops in South Korea since the Korean War ended in a truce in 1953.

Recently Pyongyang also has threatened to shut down a jointly run factory complex in the North, the remaining symbol of inter-Korean rapprochement. But officials in Seoul say hundreds of workers traveled across the heavily armed border to the North Korean factory Monday.

While analysts call North Korea’s threats largely brinkmanship, 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 several bloody battles over the years. In 2010, attacks blamed on Pyongyang killed 50 South Koreans.

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