North Korea nuclear threat: A look at North Korea's history of threats

Threats of a pre-emptive nuclear strike. Refusing to answer a hotline phone. Announcing the ending of the armistice.

Even by North Korean standards, the threats this week by leader Kim Jong Un and ensuing actions have been incredibly provocative, making the situation on the Korean Peninsula more worrisome.

Here's a look at the Kim's escalating rhetoric and his country's actions since he came to power following his father's death in 2011:

March 2012

As South Korea hosts world leaders at an international nuclear security summit in Seoul, North Korea moves a long-range rocket toward a launch pad.

Pyongyang says it plans to carry out the test in mid-April as part of a commemoration of the 100th anniversary of the birth of Kim Il Sung, the nation's founder.

April 2012

Defying warnings by U.S. President Barack Obama that Kim has nothing to gain from provocations, Pyongyang launches the rocket. It breaks apart and falls into the sea.

August 2012

Kim visits the same military unit behind a 2010 attack on South Korea's Yeonpyeong Island, where he reminds the troops to be ready to fight a "sacred war" against Seoul.

The North Korean leader makes the veiled threat just ahead of an annual war games conducted of the Korean Peninsula by the United States and South Korea.

The dictator calls the joint Seoul-Washington military exercises a "war rehearsal" to invade.

October 2012

North Korea claims to have developed missiles that can reach the U.S. mainland.

December 2012

Kim announces plans to launch another long-range rocket in a renewed effort to send a satellite into space.

Two days after the government announces the launch window is being pushed back because of technical issues, the rocket lifts off from the west coast of North Korea. Pyongyang declares the mission a success.

January 2013

North Korea announces it is planning a new nuclear test and more long-range rocket launches, all of which it says are part of a new phase of confrontation with the United States.

The threats come two days after the U.N. Security Council approves the broadening of sanctions in response to the rocket launch in December that apparently put a satellite in orbit.

February 2013

North Korea carries out an underground nuclear bomb test on February 12.

The test is designed "to defend the country's security and sovereignty in the face of the ferocious hostile act of the U.S.," the North's state-run Korean Central News Agency says at the time, referring to new U.S.-led sanctions.

"This nuclear test is our first measure, which displayed our maximum restraint. ...If the U.S. continues with their hostility and complicates the situation, it would be inevitable to continuously conduct a stronger second or third measure."

March 2013

Angered by U.N. Security Council sanctions over its nuclear test, North Korea threatens for the first time to launch a pre-emptive nuclear strike against the United States and South Korea.

It's one of a series of threat that begins with Pyongyang threatening to scrap the 1953 truce that effectively ended the Korean War. At the same time, it cuts off its direct phone links with South Korea at Panmunjom, the abandoned village that sits on the border between the two countries.

On March 8, North Korea doubles down on the threat, saying it is nullifying the joint declaration on the denuclearization of the Korean Peninsula. One of the country's top generals, according to published reports, claims Pyongyang has nuclear-tipped intercontinental ballistic missiles that are ready to be fired.

In a sign of crumbling relations, North Korea refuses to answer its hotline with South Korea, South Korea's unification ministry said Monday, according to the Yonhap news agency.

Rodong Sinmun, the official newspaper of North Korea's ruling Workers' Party, reports Monday that North Korea's army has declared invalid the 1953 armistice agreement that ended the Korean War. With the declaration, Pyongyang makes good on its threat to nullify the armistice.