New North Korean leader Kim Jong Un has delivered his first public speech since taking power, promising to guide his impoverished country to “final victory,” as the army unveiled what appeared to be a new long-range rocket.

Mr. Kim, clad in black, spoke Sunday on topics ranging from foreign policy to the economy. At one point he warned that alleged attempts by foreign powers to intimidate his country will no longer work.

“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.”

The rocket displayed in a parade through a square in central Pyongyang appeared similar to one that broke up shortly after liftoff early Friday over the Yellow Sea. Some analysts say the new rocket appeared to be a larger version of the failed mid-range missile, while others suggested it could have been a mock-up.

Before Friday’s launch, North Korea touted the blast-off as a gesture commemorating the 100th birthday of its late founding leader Kim Il Sung. Official media said the rocket would carry a weather satellite into space.

But a host of foreign governments and the United Nations condemned the launch, accusing Pyongyang of using the satellite scenario as a cover for ballistic-missile testing banned under U.N. resolutions.

In his address Sunday, Mr. Kim emphasized the importance of strengthening North Korean defenses by placing the country’s first, second and third priorities on military strength.

But he also said he would work to unify the Korean peninsula and said he is open to working with foreign countries that do not have what he called hostile policies toward Pyongyang.

He further pledged to improve the lives of rank-and-file North Koreans, who have suffered for more than a decade from famine and accompanying food shortages.

A top aide to U.S. President Barack Obama confirmed Friday that because of the launch the United States will not move forward with a plan for emergency food deliveries to the North.