South Africa had never finished on the podium in the 100m at the event before but Lemao and Retshidisitswe Mlenga ensured they claimed two medals at the Moi International Sports Centre.

Amid difficult track conditions as a result of heavy downpours in the Kenyan capital, Lemao sprinted to victory in 10.57sec, with Mlenga second in 10.61.

Tyreke Wilson continued Jamaica's sprinting tradition as he sealed the bronze medal in 10.65.

Kenya were denied home glory on the first day of the Championships as Abersh Minsewo of Ethiopia beat Emmaculate Chepkirui to secure gold in the girls' 3,000m.

In what proved to be a thrilling race, Minsewo crossed the line in 9min 24.62sec, with the Kenyan athlete a mere 0.07 adrift in silver medal position.

Ethiopia also took bronze thanks to Yitayish Mekonene, who clocked 9:28.46.

In the third and final gold medal event of the day, Germany's Selina Dantzler fought off competition from Chinese athletes Tianxiao Yu and Yue Sun to seal the girls' shot put crown.

Dantzler threw a best of 17.64 metres, edging Tianxiao by 0.02m.

Yue was the recipient of the bronze medal.

In response to security fears in Kenya in the build-up to the event, the country's Government has imposed extra cordons around the venue.

All vehicles travelling to the Moi International Sports Centre must undergo security checking more than 100 meters away from the stadium, while additional police officers are in attendance.

There are of concerns of escalating violence across Kenya prior to the country's Presidential elections in August, while the threat of terrorism also remains high.

Six countries - the United States, Australia, Britain, Switzerland, New Zealand and Canada - all withdrew prior to the event due to security fears.

Al Shabaab, a militant group in Somalia opposed to the Somali government, have also issued public threats to Kenya as a result of their military intervention in the nation.

Back in 2013, the group killed 67 people at Nairobi's Westgate Shopping Mall.

Those involved in a shooting at Garissa University College in 2015, where almost 150 people lost their lives, also claimed to be representing Al Shabaab.

"We have left nothing to chance to host secure Games," Organising Committee chief executive Mwangi Muthee was quoted as saying by Chinese news agency Xinhua.

"Those countries that pulled out will rue the day they made their decision not to attend the event."

Action in Nairobi continues tomorrow.