North Koreans got their first live look at their likely next leader Sunday as Kim Jong Il's son joined his father for a military parade marking the 65th anniversary of the ruling Workers' Party.

Kim Jong Un sat next to his father in an observation box high above the streets of Pyongyang, North Korea's capital, to watch armoured trucks, tanks and thousands of soldiers parade past in a show of military might broadcast live on state television.

The younger Kim was making his first public appearance less than two weeks after being named a four-star general, a move that sets him up to succeed his father as head of the reclusive communist state.

The two Kims alternately sat solemnly and waved enthusiastically to the crowd during the parade, which turned into a fireworks display and concert once night fell.

The pair sat above a giant portrait of their father and grandfather, North Korea's founder Kim Il Sung, as thousands of soldiers marched around the capital's main plaza alongside recruits from naval academies and nursing schools.

The sight of three generations of the Kim dynasty spurred raucous cheers from the crowd.

"Kim Jong Il! Protect him to the death!" "Kim Jong Il, let's unite to support him!" the crowd chanted as the 68-year-old leader shakily walked along the observation platform, holding onto a banister for support.

Trucks carrying katyusha rocket launchers rumbled through the square before missile and after missile rolled past, each bearing the words: "Defeat the U.S. military. U.S. soldiers are the Korean People's Army's enemy."

"If the U.S. imperialists and their followers infringe on our sovereignty and dignity even slightly, we will blow up the stronghold of their aggression with a merciless and righteous retaliatory strike by mobilizing all physical means, including self-defensive nuclear deterrent force, and achieve the historic task of unification," Ri Yong Ho, chief of the General Staff of the North Korean army, said during the parade.

Japanese television network NHK reported that three types of missiles never seen before in North Korea were part of the festivities.

The network reported seeing the new "Musudan" intermediate-range ballistic missile, which has a range of up to 5,000 kilometres.

But secondary to the military might show, the parade's goal was to begin building an image for the country's next leader, the man known as the "Young General."

After locking out foreign media for the better part of two years, North Korean officials permitted a small group of journalists into the country and gave them front-row seats to the parade, including CTV's Beijing Bureau Chief Ben O'Hara-Byrne.

It is unclear what future events will add to the younger Kim's coming-out party, given that so little is known about him that his exact age is unclear.

While experts guess he is in his mid-twenties, Kim Tae-hyo, deputy security adviser to South Korea's president, said last week the younger Kim is 26, born on Jan. 8, 1984. He is the elder Kim's youngest son and was educated in Switzerland.

He was awarded his first military post when he was given the title of general in late September during the political convention to the Workers' Party's central military commission.

"Keep in mind, up until a few weeks ago Kim Jong Un's name had never been mentioned publicly, his photo had never been seen," O'Hara-Byrne reported from North Korea. "Now he's sharing centre stage with his father."

On the southern side of the Demilitarized Zone, which separates North Korea from South Korea, protesters decried the succession process.

"North Koreans, wake up and resist the people's murderer Kim Jong Il's shameful three-generational hereditary succession of power," read one banner.

O'Hara-Byrne said the transition of power will not be an easy one.

"This is not the same country that Kim Jong Il inherited from his father, Kim Il Sung, in 1994. This is a country with deep economic problems, deep social problems (and which is) isolated in the world community," he said. "So right now this regime is doing everything it can to smooth the succession process."

With files from The Associated Press