Question: When did North Korea declare it 'is not restrained by the North-South declaration on non-aggression.'?
About the article "Korean War", section "Division of Korea (1954–present)".

Candidate passages:
  North Korea confirmed it ended the 1953 Korean Armistice Agreement, declaring that North Korea "is not restrained by the North-South declaration on non-aggression" and warned that the next step was an act of "merciless" military retaliation against its enemies.  
After Korea was divided by the UN, the two Korean powers both tried to control the whole peninsula under their respective governments.
This led to escalating border conflicts on the 38th parallel and attempts to negotiate elections for the whole of Korea.
These attempts ended when the military of North Korea invaded the South on 25 June 1950, leading to a full-scale war.
With endorsement from the United Nations, countries allied with the United States intervened on behalf of South Korea.
After rapid advances in a South Korean counterattack, North-allied Chinese forces intervened on behalf of North Korea, shifting the balance of the war.
Fighting ended on 27 July 1953, with an armistice that approximately restored the original boundaries between North and South Korea.
More than one million civilians and soldiers were killed in the war.
Although some have referred to the conflict as a civil war, other important factors were involved.
The Korean War was also the first armed confrontation of the Cold War and set the standard for many later conflicts.
It is often viewed as an example of the proxy war, where the two superpowers would fight in another country, forcing the people in that country to suffer most of the destruction and death involved in a war between such large nations.
The superpowers avoided descending into an all-out war against one another, as well as the mutual use of nuclear weapons.
It also expanded the Cold War, which to that point had mostly been concerned with Europe.
A heavily guarded demilitarized zone on the 38th parallel still divides the peninsula, and an anti-Communist and anti-North Korea sentiment remains in South Korea.
Since the Armistice in 1953, relations between the North Korean government and South Korea, the European Union, Canada, the United States, and Japan have remained tense, and hostile incidents occur often.
North and South Korea signed the June 15th North-South Joint Declaration in 2000, in which they promised to seek peaceful reunification.
On 4 October 2007, the leaders of North and South Korea pledged to hold summit talks to officially declare the war over and reaffirmed the principle of mutual non-aggression.
On 13 March 2013, North Korea confirmed it ended the 1953 Armistice and declared North Korea "is not restrained by the North-South declaration on non-aggression."
On 7 March 2013, North Korea announced its intentions to launch a preemptive nuclear strike against the United States.
The statement called the United States, the "sworn enemy of the Korean people".
On 8 March 2013, the North Korean government announced that it was withdrawing from all non-aggression pacts with South Korea in response to U.N.
Resolution 2094.
The announcement said it was closing its joint border crossing with South Korea and cutting off the hotline to the South.
On 13 March 2013, North Korea confirmed it ended the 1953 Armistice and declared North Korea "is not restrained by the North-South declaration on non-aggression.
Confirmation of the severing of the hotline between the North and the South—the last remaining communication link between the two countries at that time—was publicly announced on March 27, 2013, the same date that the hotline was cut off.
According to the Korean Central News Agency, a senior North Korean military official stated: "Under the situation where a war may break out any moment, there is no need to keep up North-South military communications" prior to the cessation of the communication channel.
On 30 March 2013, the North Korean government declared it was in 'a state of war' with South Korea.
A North Korean statement promised "stern physical actions" against "any provocative act".
The North Korean leader Kim Jong-un declared that rockets were ready to be fired at American bases in the Pacific in response to the U.S. flying two nuclear-capable B2 stealth bombers over the Korean peninsula.
The United States warned North Korea that the rapidly escalating military confrontation would lead to further isolation, as The Pentagon declared that the U.S. was "fully capable" of defending itself and its allies against a missile attack.
On 4 April 2013 North Korea's state news agency KCNA announced "The moment of explosion is approaching fast.
No one can say a war will break out in Korea or not and whether it will break out today or tomorrow."U.S.
National Intelligence Director James Clapper speculated that Kim Jong-un is trying to assert his control over North Korea, and has no endgame other than gaining recognition; analysts and other U.S. officials have echoed similar sentiments.
Four missile launches were conducted on May 18 and 19, 2013—according to South Korea's defense ministry, three short-range guided missiles landed into the waters off the Korean peninsula on May 18, followed by a fourth on May 19.
The missiles did not put any neighboring nations at risk and Pyongyang's actions were widely viewed as an exercise in fear creation to prompt other countries to consider security and aid concessions.
The launches occurred during a period when relations were strained between the North and the South, as Pyongyang refused to participate in talks over the closed Kaesong plant.
At the start of June 2013, the North Korean government offered to enter into talks that would represent the first dialogue of its kind in many years.
The South Korean government immediately accepted the proposal. 
Division of Korea (1954–present).
The Korean Armistice Agreement provided for monitoring by an international commission.
Since 1953, the Neutral Nations Supervisory Commission (NNSC), composed of members from the Swiss and Swedish Armed Forces, has been stationed near the DMZ.
In April 1975, South Vietnam's capital was captured by the North Vietnamese army.
Encouraged by the success of Communist revolution in Indochina, Kim Il-sung saw it as an opportunity to invade the South.
Kim visited China in April of that year, and met with Mao Zedong and Zhou Enlai to ask for military aid.
Despite Pyongyang's expectations, however, Beijing refused to help North Korea for another war in Korea.
Since the armistice, there have been numerous incursions and acts of aggression by North Korea.
In 1976, the axe murder incident was widely publicized.
Since 1974, four incursion tunnels leading to Seoul have been uncovered.
In 2010, a North Korean submarine torpedoed and sank the South Korean corvette ROKS "Cheonan", resulting in the deaths of 46 sailors.
Again in 2010, North Korea fired artillery shells on Yeonpyeong island, killing two military personnel and two civilians.
After a new wave of U.N. sanctions, on 11 March 2013, North Korea claimed that it had invalidated the 1953 armistice.
On 13 March 2013, North Korea confirmed it ended the 1953 Armistice and declared North Korea "is not restrained by the North-South declaration on non-aggression."
On 30 March 2013, North Korea stated that it had entered a "state of war" with South Korea and declared that "The long-standing situation of the Korean peninsula being neither at peace nor at war is finally over."
Speaking on 4 April 2013, the United States Secretary of Defense, Chuck Hagel, informed the press that Pyongyang had "formally informed" the Pentagon that it had "ratified" the potential usage of a nuclear weapon against South Korea, Japan and the United States of America, including Guam and Hawaii.
Hagel also stated that the US would deploy the Terminal High Altitude Area Defense anti-ballistic missile system to Guam, due to a credible and realistic nuclear threat from North Korea.
North Korea has announced that it will no longer abide by the armistice at least 6 times, in the years 1994, 1996, 2003, 2006, 2009, and 2013.
On April 28, 1994, North Korea announced that it would cease participating in the Military Armistice Commission, but would continue contact at Panmunjom through liaison officers and maintain the general conditions of the armistice.
North Korea stated that it regarded the U.S. deployment of Patriot missiles in South Korea as terminating the armistice.
On May 27, 2009, North Korea announced that it no longer felt bound by the armistice agreement.
There were two isolated violent incidents in 2010, the ROKS Cheonan sinking (cause disputed, but suspected to be a North Korean submarine attack) and the North Korean Bombardment of Yeonpyeong.
In 2013 North Korea argued that the armistice was meant to be a transitional measure.
North Korea had made a number of proposals for replacing it with a peace treaty, but the U.S. had not responded in a serious way.
It further argued that the Military Armistice Commission and Neutral Nations Supervisory Commission had long been effectively dismantled, paralysing the supervisory functions of the armistice.
North Korea believes that the annual U.S. and South Korean exercises Key Resolve and Foal Eagle are provocative and threaten North Korea with nuclear weapons.
JoongAng Ilbo reported that U.S. vessels equipped with nuclear weapons were participating in the exercise, and The Pentagon publicly announced that B-52 bombers flown over South Korea were reaffirming the U.S. "nuclear umbrella" for South Korea.
In March 2013, North Korea announced that it was scrapping all non-aggression pacts with South Korea, along with other escalations such as closing the border and closing the direct phone line between the two Koreas.
North Korea stated that it had the right to make a preemptive nuclear attack.
A United Nations spokesman stated that the armistice agreement had been adopted by the U.N. General Assembly, and could not be unilaterally dissolved by either North Korea or South Korea.
On March 28, 2013, the U.S. sent two B-2 Spirit stealth bombers to South Korea to participate in ongoing military exercises in the region, including the dropping of inert munitions on a South Korean bomb range.
This was the first B-2 nonstop, round-trip mission to Korea from the United States.
Following this mission, North Korean state media announced that it was readying rockets to be on standby to attack U.S. targets.
In May 2013, North Korea offered South Korea a peace treaty to replace the armistice agreement.
The U.S. position, as expressed in 2010, is that a peace treaty can only be negotiated when North Korea "takes irreversible steps toward denuclearization".