U.S. deploys stealth fighter jets to South Korea

The F-22 Raptors were sent to the main U.S. Air Force Base in South Korea amid spiking tensions on the Korean peninsula. The U.S. military command in South Korea said they were deployed to support air drills as part of the annual Foal Eagle training exercises, which are carried out in accordance with the armistice that put an end to armed hostilities in 1953. North Korea has been ramping up its rhetoric and military show of force in response to the annual joint military exercises, declaring the armistice invalid on March 11, 10 days after Foal Eagle began. It is something Pyongyang has done before during heightened tensions. The United States' participation in Foal Eagle is intended to demonstrate the country's "commitment to stability and security in the Asia-Pacific Region," the U.S. military command in South Korea said in a statement that also urged North Korea to tone down its rhetoric. "The (Democratic People's Republic of Korea) will achieve nothing by threats or provocations, which will only further isolate North Korea and undermine international efforts to ensure peace and stability in Northeast Asia," the statement said. "The North Korean leadership is urged to heed President Obama's call to choose the path of peace and come into compliance with its international obligations."

North Korea's hot rhetoric

The deployment follows fresh insults over the weekend from Pyongyang's propaganda machine comparing the U.S. mainland with a "boiled pumpkin," unable to endure an attack from a foreign foe, the state-run Korean Central News Agency reported. North Korea, on the other hand, could withstand an offensive from the outside, the report said, thanks to shelters that the government had built around the country.

But the Pentagon and the South Korean government have said it's nothing new.

"We have no indications at this point that it's anything more than warmongering rhetoric," a senior U.S. Defense Department official said late Friday. The official was not authorized to speak to the media and asked not to be named.

The National Security Council, which advises the U.S. president on matters of war, struck a similar chord, saying Washington finds North Korea's statements "unconstructive" and is taking the threats seriously.

"But, we would also note that North Korea has a long history of bellicose rhetoric and threats, and today's announcement follows that familiar pattern," said Caitlin Hayden, a spokeswoman for the security council.

The United States will continue to update its capabilities against any military threat from the North, which includes plans to deploy missile defense systems.

No, North Korea can't hit Hawaii

In an added slap, North Korea has declared that it had entered a "state of war" with neighboring South Korea, according to a report Saturday from KCNA.

"The condition, which was neither war nor peace, has ended," North Korea's government said in a special statement carried by KCNA.

Saturday's reports also asserted any conflict "will not be limited to a local war, but develop into an all-out war, a nuclear war."

South Korean President Park Geun-hye on Monday issued a warning of her own to Pyongyang.

"If there is any provocation against South Korea and its people, there should be a strong response in initial combat without any political considerations," she said in a meeting with senior defense and security officials, according to her office.

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The South: It's not new

South Korea has not, however, treated its neighbor's latest threat as imminent danger.

Seoul noted scores of its personnel had entered the Kaesong Industrial Complex -- a joint economic cooperation zone between the two Koreas situated on the North's side of the border -- on Saturday morning. Hundreds more were set to join them later in the day, seeming to suggest both sides were going about business as usual.

The South's officials said that North's threats to shut down the complex earlier Saturday were part of the North's "measures of putting military alert to highest level," but the South was taking the North's words "seriously," the South Korean Unification Ministry Press Office said.

The threats aren't "beneficial" to the development of the economic zone, the South's ministry said. Currently, 310 people work in the industrial complex, the ministry said. However, the South hasn't detected any "irregular trend" in the zone, the ministry said.

Pyongyang's declaration it was readying its missiles also did not seem to worry officials in the South.

"The announcement made by North Korea is not a new threat, but part of follow-up measures after North Korea's supreme command's statement that it will enter the highest military alert" on Tuesday, South Korea's Unification Ministry said in a statement.