Missiles are driven past the stand with North Korean leader Kim Jong Un and other high-ranking officials during a military parade marking the 105th birth anniversary of North Korea's founding father, Kim Il Sung, in Pyongyang, April 15, 2017.

North Korea's decision to stage a massive military parade in Pyongyang showing off its growing arsenal just one day before the Winter Olympics begin is a deliberate attempt to upstage the South Korean games and stir fear, according to some observers.

Thursday's parade was expected to feature thousands of goose-stepping soldiers, intercontinental ballistic missiles, tanks and other military hardware under the watchful eye of dictator Kim Jong Un. Experts were also looking for it to feature new long-range missiles and a submarine-launched ballistic missile.

Still, North Korea is sending a delegation of athletes and others to the Pyeongchang games in South Korea.

"The North has, in effect, staged a take over of the theater of the games, when they should have been a celebration of South Korea's achievements," said Peter Jennings, executive director of the Australian Strategic Policy Institute, an independent think tank. "This is a typically provocative act on the part of Kim Jong Un and shows that the North still presents a massive threat to South Korea, even if they have a combined Olympic team."

South Korea's unification minister, Cho Myoung-gyon, recently said the North's military parade "is likely to be a quite intimidating event."

The nuclear-armed regime said last month the parade was to mark its army founding day — the celebration of which had been held in April until 2015.

"I think in their view, Seoul allowed the North Koreans to partially hijack the Olympics because Seoul recognizes DPRK [North Korean] strength and made concessions out of fear," said Denny Roy, an Asia Pacific security expert and senior fellow at the East-West Center, a Honolulu-based think tank. "Now Pyongyang wants to deepen that trend."

Satellite images taken Tuesday show an estimated 13,000 troops preparing for the upcoming parade, according to the website 38 North, a think tank at the School of Advanced International Studies at Johns Hopkins. The researcher said the images showed tanks, armored personnel carriers and other combat vehicles.

According to 38 North, there normally are ballistic missiles and unmanned aerial vehicles at such parades, but they were not visible on satellite images and could have been in storage areas.

"Clearly, this parade is meant as a show of force," said former U.S. Army officer and intelligence expert Michael Pregent, an adjunct fellow at the Hudson Institute, a nonpartisan think tank.

Kim Jong Un's decision to hold the parade a day before the Olympics start could be in response to "negative South Korean press mocking" the young North Korean autocrat, Pregent added.

In the past, state media video and pictures of North Korea's parades and ballistic missile launches have been "very valuable" for obtaining information about the regime's arsenal, according to Bruce Klingner, a former CIA deputy division chief for the Korean Peninsula and national security specialist at the Heritage Foundation, a conservative Washington think tank. He said there were several missiles that were displayed last year for the first time by the regime.

"The information people are able to get from that is pretty astrounding," said Klingner. For a static rocket test, he added, observers "can literally look at the size, shape and color of the exhaust flame and determine that it is different propellant" while also learning if it's more effective or efficient.

Regardless, Pregent said the North Koreans have a track record of sometimes showing off fake weapons or exaggerating technology. Still, he said the information is important since "we do know that they do have a serious capability."