"Our launch of the reconnaissance satellite is an exercise of the right to self-defense," Kim said during a UN Security Council meeting on Pyongyang's latest satellite launch attempt.
North Korea's goal is to build its self-defense capability, Kim said.
Kim said the satellite launch did not cause any harm to the security of its neighboring country.
North Korean state media earlier reported this week that the country's second attempt to launch a spy satellite had failed, adding that in October, a third attempt will be made.
On Wednesday, the office of Japanese Prime Minister Fumio Kishida said that North Korea had launched a "suspected ballistic missile." The NHK broadcaster later reported that the missile passed over Japan and its fragments fell in the Yellow Sea, the East China Sea as well as in several other parts of the Pacific Ocean.