The North Korean ambassador to the United States spoke before the United Nations Security Council (UNSC) on Thursday. 

Ambassador Kim Song defended North Korea's test launch of an intercontinental ballistic missile on Wednesday, calling it a legitimate exercise in national self-defense. 

It was the first speech from the hermit kingdom in front of the UNSC in approximately a decade.

NORTH KOREA REQUESTS TO SPEAK AT UN SECURITY COUNCIL MEETING CALLED IN RESPONSE TO ITS LATEST MISSILE LAUNCH

South Korea’s U.N. Ambassador Hwang Joon-kook was present at the meeting as an observing member.

North Korea on Wednesday fired a submarine-launched intercontinental ballistic missile toward the East Sea, reigniting perennial tensions in the region.

NORTH KOREA FIRES INTERCONTINENTAL BALLISTIC MISSILE TOWARD EAST SEA: SOUTH KOREA MILITARY

South Korea's joint chiefs of staff announced in a statement that it detected the ballistic missile launch near the North's capital of Pyongyang, just days after the hermit nation promised "shocking" consequences to protest what it called a provocative U.S. reconnaissance activity near its territory.

North Korean dictator Kim Jong Un's sister, Kim Yo Jong, accused the U.S. of sending spy planes over the North’s exclusive economic zone, the area within 200 nautical miles of its territory where it controls rights to natural resources.

Kim Yo Jong said a U.S. spy plane crossed the eastern sea boundary between the Koreas at around 5 a.m. Monday and conducted reconnaissance activities over the North’s exclusive economic zone before being chased away by North Korean warplanes.

She also said the U.S. aircraft crossed the eastern sea boundary again at around 8:50 a.m., prompting North Korea’s military to issue an unspecified "strong warning" toward the United States.