North Korea conducted a nuclear attack just as self-defense if its sovereignty is threatened.
This was said Saturday North Korean leader Kim Jong-un, according to state local press reported.
North Korea fires short-range missiles while the US and South Korea conduct joint military exercises
Jong-un said at a rare meeting of his party that there should be more talks with South Korea to build trust and understanding.
He also said that North Korea could work to stop the spread of nuclear weapons.
The unusual congress in North Korea in which "crowned" Kim Jong-un
A BBC correspondent in North Korea said Kim tends to send mixed messages because there has been movement around the country would be preparing a new nuclear test.
Pyongyang has made repeated threats of nuclear attacks against South Korea and the United States.
Political analysts familiar with the operation of this hermetic country said they expected that during the meeting, which began Friday, Yo-jong assume an important role within the North Korean leadership.
The unusual congress in North Korea in which "crowned" Kim Jong-un
The news agency South Korean Yonhap quoted experts who say that Yo-jong could receive a ministerial level position within the Labour Party, which controls the country's destiny.
Experts believe that the appointment would be part of a larger plan of Kim Jong-un to consolidate his power within the party and the whole country.
