(CNN)North Korea staged a highly-anticipated military parade through the capital Pyongyang Thursday, a diplomatic source told CNN, an event that has so far been hidden from the rest of the world.
International media was not invited to cover the parade, which was to feature "hundreds" of rockets and missiles, diplomatic sources said last month.
South Korean news agency Yonhap reported that as many as 50,000 people gathered in Kim Il Sung square to watch the event, which included around 13,000 soldiers.
The parade began at 10:00 a.m. Pyongyang time, a diplomatic source with deep knowledge of North Korea's activities told CNN. It's possible that North Korean state television will air video of the event during its afternoon broadcast.
The parade was held around the same time as a welcoming ceremony for hundreds of North Koreans who are in South Korea for the 2018 Winter Olympics.
North Korean athletes applaud during a welcoming ceremony for the country'sOlympic team in Pyeongchang, South Korea.
For North Korean leader Kim Jong Un, the parade is an opportunity to stoke patriotic fervor and to remind the world of his country's rapid progress on its nuclear program.
For South Korea, it's a poke in the eye after efforts by President Moon Jae-in to present a united front as the two Koreas compete under the same flag.
"The North Koreans tend to act out like this even during periods of quiet to demonstrate their independence and to try to convince us that their nuclear arsenal is beyond limits," said Adam Mount, a senior fellow at the Federation of American Scientists.
"It's a clear sign of defiance, and they intend it to be."
The encore
Pyongyang's parades offer an unparalleled opportunity for intelligence analysts to get images of military equipment from one of the world's most reclusive places.
Last year, many in the open-source intelligence community that track North Korea's weapons program were surprised by the sophisticated missiles on display.