(CNN) -- North Korean leader Kim Jong Un on Wednesday made his second public speech, signaling a departure in leadership style from his late father.
Speaking to tens of thousands of children in Pyongyang on the 66th anniversary of the Korean Children's Union, Kim said the country has a good future.
"Korea's future depends on you," he said. "The Korea you are in charge of will be a country full of laughter and happiness, and also the strongest country in the world."
Kim said the country has the latest rocket technology and called on the children to study hard, saying they cannot contribute to the nation if their grades are bad.
In April, North Korea carried out a failed rocket launch that it said was to put a satellite into orbit. Other countries, including South Korea and the United States, assumed it was a coverup for testing its ballistic missile technology.
About 20,000 children were transported to Pyongyang from around the country for the occasion , state-run KCNA reported.
North Korean television showed footage of many children sobbing with emotion as their leader spoke.
Kim Jong Un also spoke at the 100th anniversary of the birth of North Korean founder, Kim Il Sung. His father, Kim Jong Il, is believed to have made only one brief broadcast throughout his reign, showing his son is creating his own individual persona.
The speech is also considered a way for Kim Jong Un to try to win over a new generation as he continues to shore up support for his hereditary succession.
A North Korean expert says the speech shows Kim Jong Un is more similar to his grandfather, Kim Il Sung, than his father, which is what the nation's propaganda machine has emphasized.
"His grandfather, unlike his father, was a reasonably good speaker, not charismatic, but he could talk for hours if necessary and was clearly not shy when it came to talking in public, it was part of the image," said Professor Andrei Lankov of Kookmin University.