North Korea's new leader gave his first public speech on Sunday since taking power, portraying himself as a strong military chief unafraid of foreign powers as the army showed off what appeared to be a new long-range missile.

Kim Jong Un's lengthy speech - two days after North Korea launched a long-range rocket in defiance of international warnings - took North Koreans gathered at Kim Il Sung Square and before televisions across the country by surprise. His father, late leader Kim Jong Il, addressed the public only once in his lifetime.

Calm and measured, Kim Jong Un covered a wide range of topics, from foreign policy to the economy, as he spoke during choreographed festivities honoring the 100th birthday of his late grandfather, North Korean founder Kim Il Sung.

The rocket unveiled Sunday, which appeared to have several stages, was similar to the one that broke into pieces over the Yellow Sea shortly after liftoff Friday, but was of a more overtly military design.

While it's not clear how powerful or significant this addition to the North Korean arsenal is - or whether it was a mock-up - it signaled that North Korea is continuing to build up its military despite the failed launch.

Although that launch was a huge, costly embarrassment, Kim's address Sunday was seen by analysts as an expression of confidence by the young leader and meant to show that he is firmly in control.

"Superiority in military technology is no longer monopolized by imperialists, and the era of enemies using atomic bombs to threaten and blackmail us is forever over," Kim said.

Kim's words often mirrored what North Korea regularly says in its state media, but there was symbolism in the images of the new leader, who is believed to be in his late 20s, addressing the country on state TV and then watching - and often laughing and gesturing in relaxed conversation with senior officials - as a parade of North Korean military troops and hardware marched by.

Outside analysts have raised worries about how Kim, who has been seen but not publicly heard since taking over after his father's December death, would govern a country that has a nuclear weapons program and has previously threatened Seoul and Washington with war.

The speech was a good "first impression for his people and for the world," said Hajime Izumi, a North Korea expert at Japan's Shizuoka University. "He demonstrated that he can speak in public fairly well, and at this stage that in itself - more than what he actually said - is important. I think we might be seeing him speak in public more often, and show a different style than his father."

Kim emphasized the importance of strengthening North Korea's defenses by placing the country's 'first, second and third' priorities on military might. However, he also said he is open to working with foreign countries that do not have hostile policies toward his nation, and said he would strive to reunify Korea.

"It's a heartbreaking fact that our nation has been divided for more than 70 years," he said.

Kim also stressed the importance of national unity, calling his country 'Kim Il Sung's Korea' rather than North Korea. In recent days, the square bearing his grandfather's name has been redecorated, with the Marx and Lenin portraits that adorned key buildings taken down and replaced with long red banners vowing to defend the new leader 'to the death.' At the front are portraits of the two late leaders, Kim Il Sung and Kim Jong Il.

"That suggests to me that they want to let the country, and the world, know that this is a 'new' country," said Han S. Park, a University of Georgia professor who works frequently with top U.S. and North Korean officials, after watching the events in Pyongyang.

The young leader also underlined his commitment to aggressively building the economy and improving people's daily lives.

North Korea has suffered decades of economic hardship following a famine in the mid-1990s and the loss of aid from the Soviet Union. Kim Jong Un's formal three-year succession has coincided with a push to improve the economy by employing modern technology.

Kim's speech was "an expression of confidence," said Kim Yeon-su of Korea National Defense University in South Korea. "Kim Jong Un is trying to dispel lingering doubts about his grip on power."

North Korea is in the midst of two weeks of celebrations marking Kim Il Sung's birthday and the upcoming 80th anniversary of the Korean People's Army. But it has also become a showcase of Kim Jong Un's new era of leadership, with Kim giving the world a taste of his foreign policy by firing the rocket Friday in defiance of outside criticism.

In a surprise admission, North Korea's state media announced hours after the launch that the attempt to send a satellite into space was a failure.

Condemnation abroad was swift, and the launch - using the same type of rocket technology used for firing a long-range missile - raised concerns that a nuclear test might be next.

The finale in Sunday's military parade was the new long-range missile.

Military analysts in Japan and South Korea said further examination is needed to determine whether it's a new intercontinental ballistic missile that North Korea reportedly has been building.

The exact design could not immediately be confirmed by North Korean military officials. A number of North Koreans at the parade said it was the first time they had seen the missile.

Narushige Michishita, a North Korea military expert at Japan's National Graduate Institute for Policy Studies, said the missile appeared to be new, but strongly resembled the rocket used on Friday and also the long-range Taepodong-2, which North Korea first launched, unsuccessfully, in 2006.

He said it probably has three stages but did not appear to be big enough to have the 15,000-kilometer (9,000-mile) range needed to effectively attack the United States, which would be the goal of an ICBM for the North.

"I don't think this is a serious ICBM," Michishita said. "Putting it on display has a psychological impact, and that would have been greater if Friday's launch had worked. But North Korea has a very bad record with long-range missiles. It think this is more a propaganda ploy than a military advance."