(CNN) North Korea put its military might on display during a parade in the heart of Pyongyang while the regime showed off some of its latest arsenal.

Pictures on state television showed thousands of soldiers marching in formation alongside tanks, balloons and enormous crowds.

Leader Kim Jong Un was shown clapping and smiling from a reviewing box.

At one point, the soldiers directed a chant toward him.

"We will die for you!" they yelled, CNN's Will Ripley, who was at the event, reported.

During the pomp and circumstance at Kim II Sung square, citizens showed their revolutionary fervor with choreographed performances while vehicles displaying North Korea's military arsenal rolled by.

"We saw a submarine launch ballistic missiles, we saw missiles that are capable of being launched from a mobile launcher and just seconds before we came on the air we saw these very large what are believed to be intercontinental ballistic missiles," Ripley said as jets tracked colors of the North Korean flag in the sky during the parade.

In a live broadcast, a newsreader from North Korea's state-run television service called the new military hardware the country's "modernized strategic missiles."

"No nation in the world develops missiles and shows the real thing during a parade, it's just too dangerous," Markus Schiller, a weapons expert with ST Analytics, told CNN that parades always involve "mock-ups". "If anything happens, it blows up, right next to the 'Dear Leader'."

Photos: North Korea Day of the Sun parade North Korean leader Kim Jong Un waves during a military parade on Saturday, April 15, 2017, in Pyongyang to celebrate the 105th anniversary of Kim Il Sung's birth, the country's late founder and grandfather of current ruler Kim Jong Un. Hide Caption 1 of 17 Photos: North Korea Day of the Sun parade Soldiers in tanks take part in the military parade. Hide Caption 2 of 17 Photos: North Korea Day of the Sun parade North Korean soldiers carry flags and a photo of late leader Kim Il Sung as they march across Kim Il Sung Square. Hide Caption 3 of 17 Photos: North Korea Day of the Sun parade Female North Korean soldiers march during the parade. Hide Caption 4 of 17 Photos: North Korea Day of the Sun parade Missiles are paraded across Kim Il Sung Square. Hide Caption 5 of 17 Photos: North Korea Day of the Sun parade A rocket-themed float makes its way through Kim Il-Sung square. Hide Caption 6 of 17 Photos: North Korea Day of the Sun parade Soldiers salute while the national anthem is played during the parade. Hide Caption 7 of 17 Photos: North Korea Day of the Sun parade Women wearing traditional Korean dress wave flowers and shout slogans as they pass North Korea's leader Kim Jong-Un. Hide Caption 8 of 17 Photos: North Korea Day of the Sun parade A submarine-launched ballistic missile is displayed during the parade. Hide Caption 9 of 17 Photos: North Korea Day of the Sun parade A soldier stands guard at the Kim Il Sung Square. Hide Caption 10 of 17 Photos: North Korea Day of the Sun parade Korean citizens spell out "Day of the Sun" in Kim Il Sung Square. Hide Caption 11 of 17 Photos: North Korea Day of the Sun parade University students carry the national flag and two bronze statues of the late leaders Kim Il Sung and Kim Jong Il. Hide Caption 12 of 17 Photos: North Korea Day of the Sun parade Helmeted servicemen march during the parade. Hide Caption 13 of 17 Photos: North Korea Day of the Sun parade Korean People's Army soldiers march on Kim Il-Sung square. Hide Caption 14 of 17 Photos: North Korea Day of the Sun parade North Korean men and women dressed to represent doctors and other medical workers during the parade. Hide Caption 15 of 17 Photos: North Korea Day of the Sun parade Members of the Korean People's Army ride on mobile missile launchers. Hide Caption 16 of 17 Photos: North Korea Day of the Sun parade North Korean men beat drums as they parade across the square. Hide Caption 17 of 17

For North Koreans, April 15 is an auspicious date that sees millions celebrate the birth of the nation's founder.

Tens of thousands descended on the streets of the capital as the nation marks the 1912 birth of Kim Il Sung, grandfather of Kim Jong Un.

This year's celebrations come at a tense time on the Korean Peninsula, days after a US strike group was deployed to the region and amid expectations of another missile or nuclear test by Pyongyang.

North Korean state media warned that such "reckless acts of aggression" would be countered with "whatever methods the US wants to take."

North Korean soldiers carry flags and a photo of late leader Kim Il Sung as they march across Kim Il Sung Square during a military parade on Saturday.

"If the US does any reckless provocation, we will immediately apply a destructive strike with our revolutionary power. We're prepared to respond to an all-out war with an all-out war and we are ready to hit back with nuclear attacks of our own style against any nuclear attacks," Choe Ryong Hae, a senior member of the Presidium of the Political Bureau of the Workers' Party of Korea (WPK) said in a speech during the large military parade.

Kim Jong Un walks on the red carpet before the parade.

Tension has been building since Kim Jong Un announced in his New Year's message that the country was close to testing an intercontinental ballistic missile.

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It has since conducted a number of shorter-range missile tests -- some of which landed in the sea, less than 200 miles off the Japanese coast.

It's also conducted engine tests that analysts say could potentially power a long-range missile

US President Donald Trump held talks with Chinese President Xi Jinping at his Mar-a-Lago resort last Friday to push his case for China to do more to rein in North Korea's nuclear ambitions. They then spoke Tuesday by phone, in a call Trump described as "very good."

However, days later, he tweeted: "North Korea is looking for trouble. If China decides to help, that would be great. If not, we will solve the problem without them! U.S.A."

North Korea says it's created a nuclear weapon small enough to mount on a missile, though many experts dispute that claim.

North Korea is looking for trouble. If China decides to help, that would be great. If not, we will solve the problem without them! U.S.A. — Donald J. Trump (@realDonaldTrump) April 11, 2017

Day of the Sun

The Day of the Sun is a public holiday usually marked by grand military parades, mass celebrations and other large displays of national pride.

In recent days, North Koreans have been seen practicing choreographed dance routines in brightly colored national dress.

Before the event, foreign journalists invited into the country to report on the occasion were entertained by children at the Children's Cultural Palace on the outskirts of Pyongyang.

Children with fans entertain foreign journalists.

An enormous amount of work goes into preparing for April 15.

Joseph Bermudez, an analyst for North Korean monitoring group 38 North, said preparations could even be seen on satellite images, which showed thousands of people and hundreds of vehicles practicing ahead of the event.

Monday, hundreds of members of the Korean People's Army (KPA) crowded the plaza of the Kumsusan Palace of the Sun in Pyongyang to pay tribute to past leaders and vow loyalty to Kim Jong Un, according to state media Rodong Sinmun.

Members of the Korean People's Army (KPA) attend a ceremony at Kumsusan Palace of the Sun on Monday to mark Day of the Sun.

Kim Il Sung died in 1994 at the age of 82, after leading his country from its establishment in 1948 until his death.