North Korean leader Kim Jong Un attended a giant celebration of the country's main youth league on Sunday night, capping the organization's first gathering in more than 23 years.

The Kim Il Sung Socialist Youth League plays a major part in North Korea's social system. Young people from the ages of 14 to 30 are expected to join and take part in activities ranging from study sessions to helping out in major construction projects. North Korea says the youth league has 5 million members.

Pyongyang's May Day Stadium, which has a capacity of 150,000, was almost full Sunday night, and the crowd stood and cheered as Kim Jong Un walked in.

The event lasted just over an hour, with thousands of torch-carrying youths rushing around the stadium in formation, making patterns, symbols and slogans. Fireworks burst above the stadium at the show's climax.

North Korean state media did not immediately report on what took place at the 9th Congress of the youth league, which ran Friday through Sunday. Foreign media were not allowed in.

The 8th Congress was held in February 1993.