On Friday night North Korea said it had entered a state of war against South Korea.

American officials have responded.

"North Korea has a long history of bellicose rhetoric and threats and today's announcement follows that familiar pattern," Caitlin Hayden, a spokeswoman for National Security Council (which advises the U.S. president on matters of war), told CNN.

“Putting on a show is not the same as taking action,” an unnamed senior administration official told The Washington Post. “Describing the situation as akin to war is not to be remotely confused with wanting a war, let alone going to war.”

"We have no indications at this point that it's anything more than warmongering rhetoric," an unnamed senior Washington defense official told CNN.

On Friday night Jungah Lee of Bloomberg reported that North Korea's state-run news agency released a statement saying the U.S. stealth bomber flights over South Korea Thursday were an “unacceptable” provocation, and it was giving a “final warning” to U.S.

South Korea's Yonhap News reported that there was "an emergency military meeting convened by leader Kim Jong-un on Thursday in which he reportedly approved plans for striking U.S. and South Korean targets." On Thursday Yonhap cited an unnamed military source in reporting increased activity at North Korea's mid- to long-range missile sites.

Early Saturday Max Fisher of the Post published the North's full statement, which he described as "typical, chest-thumping North Korean rhetoric that hits the usual points."

The two Koreas have been at war since their 1950-53 conflict finished in a cease-fire (as opposed to a formal peace treaty).

North Korean threats are often for domestic consumption, but Kim has taken the bombast to a new level this year.

Early this morning the North released photos which appear to show a missile strike plan to target four cities in the U.S.

Belligerent rhetoric from Kim has been escalating ever since the UN Security Council levied biting sanctions against the country following a long-range rocket launch in December and a nuclear test in February.

Tensions reached a fever pitch this month as the U.S. and South Korea performed annual joint military exercises.

The U.S. has said that it takes North Korea's persistent threats seriously and has planned for the nuclear-armed country's collapse.

America has wartime operational control of the South Korean military in the event of a provocation.