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.