SEOUL, South Korea – Newly in charge of North Korea, where leaders are idolized but rarely heard from, Kim Jong Un on Sunday stepped onto a balcony in Pyongyang overlooking tens of thousands. He moved toward a podium affixed with seven identical microphones. And then he spoke.

The young leader, in his first public address, told a packed crowd of soldiers and citizens that he would follow the legacy of his father and grandfather and prioritize the country’s military strength.

In the speech broadcast on state television, Kim recited the points emphasized in Pyongyang’s propaganda, saying he wouldn’t be intimidated by foreign aggressors.

But the speech marked a stark reversal from the style of late leader Kim Jong Il, whose voice was heard publicly only once by North Koreans: when he shouted “Glory to the heroic Korean People’s Army” at a military parade in 1992.

Kim’s Sunday speech lasted about 20 minutes. He spoke assuredly but fixed his eyes on his notes. When he finished, he remained on the observation deck overlooking Kim Il Sung square, clapping and saluting while he watched a massive military parade.

“Superiority in military technology is no longer monopolized by imperialists,” Kim said.

Beginning with a failed rocket launch and a series of political conferences, North Korea has tried to use this week — its biggest national holiday in decades, celebrating the centennial of Kim Il Sung’s birth — to both honor its national founder and confirm its emergence into prosperity.

The reality is different: Pyongyang depends on foreign aid and domestic brutality, its system held together by government surveillance and the threat of labor camps, where as many as 150,000 are imprisoned, according to Western estimates.

The country’s living standards have fallen since the 1970s, but Kim’s speech Sunday, experts said, showed that the country is trying to tie the new leader to his grandfather, who presided over the decades for which some North Koreans feel nostalgic. Kim Il Sung delivered occasional public speeches, also in a low and commanding voice.

“By putting the young guy out front, with a similar style of speaking, this is a very orchestrated comparison” between Kim Jong Un and Kim Il Sung, said Kongdan Oh Hassig, a North Korea researcher at the Alexandria, Va.-based Institute for Defense Analyses.

The impoverished North spent an estimated $1 billion on preparations for the weekend, said Cho Bong-hyun, an analyst at IBK Economic Research Institute. Even so, Cho said, the celebration amounted to a vast “optical illusion.”

The country renovated apartment buildings in the showcase capital of Pyongyang, but it pulled students from university classes to help with the construction. It built a new hydroelectric power plant, but it hasn’t yet offset severe power shortages that allow for only two hours daily of electricity, according to reports from aid groups that operate in the North. The country also attempted to blast a long-range rocket into orbit Friday, but the device disintegrated 90 seconds into the flight and fell into the Yellow Sea.