The candidacy of the Kenyan capital was formally endorsed by the IAAF Council during the first day of its meeting in Buenos Aires.

The decision to award Nairobi the biennial event follows a successful IAAF World U18 Championships there last year. 

Crowds of up to 60,000 attended the Championships at the Moi International Sports Centre.

"Athletics is a very important part of our life," Kenya's Principal Secretary for Sports in Kenya, Ambassador Kirimi Kaberia told IAAF President Sebastian Coe during a recent visit to the world governing body's headquarters in Monaco.

"Everyone loves athletics in Kenya. 

"You saw it during the world under-18 and you will see it again in 2020."

Strong Government support for the Championships was among the main factors to award Nairobi this latest event, Coe admitted.

"The U20 Championships showcases the future of our sport so Kenya, with a young and enthusiastic population and such a rich history in athletics, is a perfect fit for us," he said.

"We hope that awarding these championships will further encourage the development of athletics in Kenya and all over Africa, which is such a vibrant part of our International Federation."

The decision to award Nairobi the event - due to take place between July 7 and 12 in 2020 - also leaves the city in a strong position to host the 2025 IAAF World Championships, when the event is expected to be awarded to an African country for the first time.  

The IAAF are expected to pick a preferred choice for the 2023 IAAF World Championships on the second day of its meeting in Argentina's capital tomorrow, with Budapest the favourite. 

"On behalf of the Kenyan Government, I would like to say that we welcome the decision that has been reached by the IAAF top brass to settle on the Republic of Kenya to host the prestigious IAAF World U20 Championships in the year 2020," Kenya’s Cabinet Secretary for Sports and Heritage Rashid Echesa said.

"It is indeed a great honour to be considered and selected to host the event. 

"I assure you that we will ensure that we put our best foot forward and put the necessary plans, systems and structures in place to ensure that the event runs smoothly and successfully."

The competition was launched as the IAAF World Junior Championships in Athletics in 1986, when it was held in Athens,and the current name of the competition was adopted in November 2015.

This year's event was held earlier this month in Tampere in Finland.

Notable athletes to have won medals at the Championships include Ethiopia's Haile Gebrselassie, winner of the 5,000 and 10,000 metres at Seoul in 1988, and Usain Bolt, who won the 200m at Kingston in 2002. 

"The Executive Committee of AK (Athletics Kenya), athletes and entire athletics fraternity are very excited to receive the good news from the IAAF that Kenya has been selected to host the World U20 in 2020," Jackson Tuwei, President of Athletics Kenya, said. 

"It is indeed a great honour to us all, particularly the great athletes who have significantly contributed to the development of world athletics over the years. 

"All are welcomed back to Kenya, the home of heroes."