The country's Academy of Defence Science and the Missile Administration conducted tests of an electromagnetic weapon system, carbon fibre bombs, a mobile short-range anti-aircraft missile system, and a tactical ballistic missile's cluster bomb warhead between Monday and Wednesday, according to the KCNA.
Analysts see the tests as likely to be a show of force in cutting-edge conventional weapon systems by the nuclear-armed North for its adversaries and allies.
Chinese Foreign Minister Wang Yi is scheduled to make a two-day visit to North Korea starting on Thursday. There has also been speculation that US President Donald Trump may try to hold a summit with North Korean leader Kim Jong-n on the sidelines of his visit to China in mid-May.
Without specifying the number of ballistic missiles launched - a violation of United Nations sanctions - North Korea said it had tested its mobile short-range anti-aircraft missile system as well as the combat capabilities of its tactical ballistic missile warhead.
One test proved the surface-to-surface tactical ballistic missile called Hwasongpho-11 Ka, which is tipped with a cluster-bomb warhead, was able to "reduce to ashes any target" covering an area of up to seven hectares, KCNA said.
The tests also follow North Korea reiterating its characterisation of South Korea as a "hostile enemy," dashing recent hopes in Seoul of easing tensions on the Korean Peninsula.
North Korea appears to be upgrading its weapon system with cutting-edge technology suited for a modern war, said Lim Eul-chul, a professor at Kyungnam University in South Korea.
The electromagnetic weapon system could have the capacity to disable electronic circuits in the enemy's assets, with the potential ability to cripple South Korea's F-35A stealth fighter jet or Aegis-equipped destroyers, Lim said.
North Korea also said it conducted a firing drill using "low-cost raw materials," indicating its target for the mass production of weapons, said Yang Moo-jin, a professor at the University of North Korean Studies.
The unveiling of such weapons would complicate South Korea's defence strategy against North Korean threats, said Song Seong-jong, a professor at Daejeon University and a former official at Seoul's Defence Ministry.
