Sweden's Sarah Sjöström broke the women's 100m butterfly world record for the second time in 24 hours to win gold in the final at the world swimming championships on Monday. The 21-year-old clocked 55.64 seconds in the final to shave 0.15secs off the record she set in Sunday's semifinal. Denmark's Jeanette Ottesen took silver in 57.05 with China's Lu Ying claiming bronze with 57.48.

Also a winner in Kazan, Russia, was Britain's Adam Peaty. The 20-year-old won the men's 100m breaststroke gold on his world championship debut, swimming 58.52 seconds to beat Olympic champion Cameron van der Burgh of South Africa by 0.07secs on the wall. Britain's Ross Murdoch took bronze at 0.57secs back.

Earlier, American teenager Katie Ledecky set a new world record in the final heat of the 1500m freestyle with a time of 15:27.71. "I think breaking that record is just a testament to the work I've put in and the shape that I'm in right now ... that I was able to do that, I'm in quite a bit of shock right now."

Ledecky, who has already won the 400m free, is the odds-on favorite to retain her title in the Tuesday final having qualified more than 26 seconds ahead of Denmark's Lotte Friis, the second fastest women in the world.