GABORONE, May 11 (Xinhua) -- A host of top marathon runners from around the world are expected to descend into Botswana capital Gaborone this weekend for the annual Gaborone Marathon slated for Sunday.

According to the race spokesperson Thabo Makgato, over 6,000 runners have registered for this year's event as it keeps on growing to become one of the biggest races in Africa.

Makgato said they have registered runners from around the world including the United States, Europe as well as many from around Africa.

This year saw the organizers setting a prize money one million Pula (98,000 U.S. dollars) for the overall winner if they beat the set time of 2:08:00.

Makgato said this was necessary as they wanted to attract more top runners to the marathon thus improve the standard of competition. He said the race has one of the flattest and fastest routes in the region and therefore it is very much possible to break the set time.

Apart from the main 42.2km marathon, there is the 21.1km half marathon, the 10km race as well as a 4km fun run and walk.

Makgato said the marathon does not only attract competitive runners, but general marathon enthusiasts as well as those doing it for fitness and leisure.

The marathon is accredited by the IAAF and it is used by runners to qualify for major events like the Olympic and Commonwealth games.

The marathon was started in 2010 and for three years it was won by Kenyans Simon Njoroge (2010) Felix Kangogo (2012), Luka Chelimo (2013).

Lesotho's Masilo Matjiane won the 2014 edition, and the 2015 and 2016 editions were won by Zimbabwean Gilbert Mutandiro, who became the first runner to defend the title.

Last year the winner was Paulus Liyambo from Namibia.

Meanwhile local runners who have been improving steadily throughout the years are also expected to give the visitors a tough competition.

In 2015 the organizers started a program to support local runners through training camps and sending them to other races. The program showed positive signs last year as the local dominated and won the 21.1km half marathon as well as the 10km race.