Pyongyang, North Korea (CNN) North Korea celebrated its national day with a series of massive spectacles glorifying 70 years of rule by the Kim dynasty Sunday, but held back on any mention of its nuclear weapons program -- a possible signal of support for Pyongyang's ongoing negotiations with the United States.

The day began with a smaller-than-expected military parade -- which did not include the ballistic missiles believed to be capable of targeting the United States -- and ended with the first Mass Games in five years.

An estimated 100,000 performers participated in Sunday night's Games, a highly-choreographed propaganda spectacle in which participants act as human pixels, flipping colorful cards to reveal socialist messages that glorify North Korea.

Unlike previous years, the Games also refrained from referencing the country's nuclear weapons program during the performance.

Experts speculated before the Sunday holiday that North Korean leader Kim Jong Un may choose not to showcase images of the country's more advanced weaponry during the anniversary celebrations to avoid antagonizing US President Donald Trump.

President Trump tweeted a thank you to North Korean leader Kim Jong Un Sunday night Washington time, noting the fact that Pyongyang chose not to showcase its long-range nuclear missiles in its morning military parade,

North Korea has just staged their parade, celebrating 70th anniversary of founding, without the customary display of nuclear missiles. Theme was peace and economic development. "Experts believe that North Korea cut out the nuclear missiles to show President Trump...... — Donald J. Trump (@realDonaldTrump) September 9, 2018

...its commitment to denuclearize." @FoxNews This is a big and very positive statement from North Korea. Thank you To Chairman Kim. We will both prove everyone wrong! There is nothing like good dialogue from two people that like each other! Much better than before I took office. — Donald J. Trump (@realDonaldTrump) September 9, 2018

But some North Korea analysts believe the country chose not to show off its long-range missiles because Pyongyang believes its program is complete, so it no longer needs to flaunt the weaponry.

The day parade saw dozens of military vehicles and goose-stepping soldiers parade past Kim in the center of the capital, Pyongyang, as cheering crowds watched on.

Soldiers march during a military parade in North Korea.

Kim reviewed the procession from a balcony in Kim Il Sung Square, alongside other senior officials, including Li Zhanshu, a special envoy sent by Chinese President Xi Jinping. Kim and Li locked hands and raised arms at the end of the event.

North Korean leader Kim Jong Un, right, raises hands with Chinese envoy Li Zhanshu.

The parade was split into two sections, civilian and military. The military portion featured thousands of soldiers wearing uniforms from different periods of North Korea's history, dating back from 1948 through to the present day.

Airplanes forming the number 70 fly in formation and fire flares during the parade.

The event was the first show of military might in North Korea since Kim and Trump met in Singapore in June.

Though some of the artillery pieces on display featured anti-American slogans as in previous years, the theme of the parade appeared overwhelmingly focused on economic development and improving the lives of the North Korean people.

North Koreans celebrate the country's 70th anniversary.

Kim did not speak at the military parade. The country's ceremonial head of state, Kim Yong Nam, addressed the audience, telling soldiers to prepare simultaneously to fight a war but also be ready to battle for economic development.

"Compared to past parades they really pulled back on displaying missile systems," said Dave Schmerler, a research associate at the James Martin Center for Nonproliferation Studies.

Kim has made 2018 a year of diplomacy, personally meeting with the leaders of China, South Korea and the United States for the first time since taking the reins of his country in 2011. Later this month, Kim will host South Korean President Moon Jae-in for a summit in Pyongyang, another event that could factor into the theme of Sunday's festivities.

North Koreans march in Kim Il Sung Square as part of Sunday's civilian parade.

Though it was the first celebration in recent years not to honor the country's nuclear achievements, the emphasis on domestic livelihoods and economic growth align with Kim's current policy priorities.

"The big missiles weren't out there. That is a clear sign of restraint on Kim Jong Un's part," said John Delury, a professor of International Relations at Yonsei University's Graduate School of International Studies.

"The symbolism of the event reinforces Kim Jong Un's message that it's the economy, stupid."

Participants perform in the Mass Games at the May Day stadium in Pyongyang, Sunday night.

But negotiations between North Korea and the United States over Pyongyang's nuclear weapons programs appear to have hit an impasse.

A little more than a month after Trump and Kim's historic summit in Singapore, US Secretary of State Mike Pompeo told US lawmakers Pyongyang had shown little indication that it was moving toward denuclearization. That was followed by Pompeo canceling a planned trip to North Korea in August, citing insufficient progress on the part of North Korea.

In the run up to Sunday's parade, both Washington and Pyongyang struck more of an upbeat note. South Korean officials who met with Kim last week said they were told by the young North Korean leader that he has "unwavering trust for President Trump."

Trump responded by tweeting a thank you to Kim and declaring "we will get it done together!"

Soldiers inside North Korea's Kim Il Sung square.

On Saturday, the US State Department said that Pompeo has received a letter from Kim for Trump, which the US President believes will be positive in tone.

Experts, however, caution against reading too much into any sense of optimism.

A soldier is seen during celebrations for North Korea's 70th anniversary.

"The United States should not forget about North Korea's arsenal simply because it's kept out of sight," said Adam Mount, director of the Defense Posture Project at the Federation of American Scientists.

"Even as talks have ground to a halt, every indication is that research and development of nuclear capable systems is continuing."

North Korea analysts are closely watching this weekend's festivities, as Pyongyang is known to use mass events like these to convey its policy priorities and future intentions to average North Koreans and the rest of the world.

Journalists were invited to a concert Saturday night to kick off the celebration, an event dominated by songs and performances lionizing North Korea's history. There was no mention of missiles or nuclear weapons.

Kim's bodyguards appeared to show up at the event, but there was no sign of the young leader himself. Footage from North Korean state television appeared to show Kim greeting the Russian delegation Saturday night.

In this photo provided Sunday by the North Korean government, North Korean leader Kim Jong Un, center, visits the Kumsusan Palace of the Sun in Pyongyang, North Korea. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government.

Sunday's parade was kept under wraps until it was completed, with visiting journalists invited to the event prohibited from bringing phones or live broadcasting equipment to the procession.

Performers take part in Saturday's concert.

It's unclear why North Korea chose to bar reporters from broadcasting live from the event, though the delay allows Pyongyang's propaganda officials to better control the images coming from the parade. Experts also believe it could be a security measure.