Semenya has not been beaten in the 800m since September 2015

Caster Semenya says she will not race at the World Championships in Qatar later this year if she loses an appeal against IAAF rules governing testosterone levels in female athletes.

The South African, 28, is the reigning 800m Olympic and world champion and won over the distance in Sunday's Diamond League meet in California.

She said: "If I'm not running 800m, I'm not running in the world championships.

"My goals are to defend my world title. So if I'm not allowed I'm not allowed."

She added: "No 1,500m, no nothing. I'm just going to take a vacation and then come back next year."

Semenya is currently challenging the International Association of Athletics Federations' new rules that she and other athletes with differences of sexual development (DSD) must either take testosterone-reducing medication in order to compete in track events from 400m to the mile or change to another distance.

She can race while she appeals and she won the 800m in California in one minute 55.69 seconds, nearly three seconds quicker than second-placed Ajee Wilson of the US.

It was the fastest 800m run by a woman on US soil and the twice Olympic champion has now not been beaten in the 800m since September 2015.

Elsewhere, Great Britain's Dina Asher-Smith was third in the women's 200m as Nigeria's Blessing Okagbare won in 22.05 seconds, with Jamaica's 200m Olympic champion Elaine Thompson second in 22.21secs.

Asher-Smith, who won the event at the Doha and Stokholm meets, ran 22.42s.

Britain's Laura Muir was in action in the women's 1500m and the Scot, European champion over the distance, ran 3:59.47 to finish behind Kenya's Olympic and world champion Faith Kipyegon (3:59.04).

In the men's 100m, American Christian Coleman won in 9.81secs, the fastest time in the world this year, beating 37-year-old compatriot Justin Gatlin, who was second in 9.87secs, and third-placed British sprinter Zharnel Hughes (9.97).

Ivory Coast's Marie-Josee Ta Lou won the women's 100m in 11.02secs, with Americans Aleia Hobbs (11.04) and Teahna Daniels (11.13) in second and third respectively.

Jamaica's two-time Olympic gold medallist Shelly-Ann Fraser-Pryce struggled in the race as she finished seventh in 11.39secs.