Standing beside North Korea's largest missiles, leader Kim Jong Un defended his country's weapons development on Monday.
State media carried comments from Kim, saying it was necessary to increase the North's military for self defense in the face of hostile policies from the U.S and South Korea.
Kim made his comments in a speech at the Defense Development Exhibition on Monday, according to a report by state news agency KCNA.
Photos in the ruling party newspaper showed Kim standing next to the country's largest intercontinental ballistic missiles, that have been unveiled, but not yet test fired.
A spokesperson for South Korea's defense ministry said they are monitoring the situation closely.
South Korea recently test fired its first submarine-launched ballistic missile, and has bought American-made F-35 stealth fighters.
North Korea has pushed ahead with its missile program, and analysts say it has begun a major expansion of its main nuclear reactor, for fuel for nuclear bombs.
The U.S has said it is willing to hold diplomatic talks at any time with Pyongyang.