In total, 36 delegations took part from four continents, with Uganda the first team to arrive and Mexico the last.

Volleyball was the first sport to get underway, on Sunday (September 12), with Montenegro opening the girl's tournament against Serbia and Croatia playing the first game of the boy's tournament against Bulgaria - Montenegro and Bulgaria ran out respective winners.

All ISF events were suspended in 2020 due to the coronavirus pandemic, with the Under-15 World School Sport Games marking a welcome return to sporting competition for the organisation.

During the first heads of delegation meeting, Serbian School Sport Federation President Željko Tanasković said it was an "honour" for Belgrade to be hosting the event.

"This competition will be special for Serbia because finally younger students will have the opportunity to compete internationally, as well as meet and socialise with their peers from around the world," said Tanasković.

For many of the participants in the ISF Under-15 World School Sport Games, this will be their first time competing in a multi-sport international event.

Two participants from Romania, Hanna Sover and Andrei Pacurar, described school sport as "important for making new friendships", while Nakiyemba from Uganda said added that "whenever you play, you need to have the feeling you will win."

Various meetings took place on the opening day of competition, including between the President of United World Wrestling (UWW) Nenad Lalovic and ISF secretary general Hrvoje Custonja.

Lalovic described wrestling as a "natural" sport for young people, saying: "In terms of development, wrestling exists in all parts of the world but what matters is to provide the appropriate conditions in terms of coaching specially to avoid injuries and to educate the new countries or participating groups to be at similar levels.

"We believe that our sport should be one of the most natural sports with the human body and human psychology and must be hugely represented in education system in schools."

The UWW is one of a number of organisations running activities in the Fun and Skills Zone, which is open daily throughout the event, with others including the Badminton World Federation and Global Esports Federation.

The World Anti-Doping Agency, the International Fair Play Committee and Kinder are also running interactive stations in the Fun and Skills Zone, which focuses on topics including gender equality, environmentally friendly, fair play, nutrition, anti-doping, clean sport, safeguarding and Olympic values.

The ISF Under-15 World School Sport Games feature 2500 participants from 42 countries competing across 14 sports - athletics, badminton, basketball, 3x3 basketball, chess, football, judo, karate, orienteering, swimming, table tennis, taekwondo, volleyball and wrestling.

A full schedule and list of results from the Games are available here.