American Rebecca Soni broke the women's 200m breaststroke world record with a time of 2min 20.00sec in the semi-finals at the London Olympics on Wednesday.

Olympic champion Soni reached the final in emphatic style as she bettered the previous world record of 2:20.12, set by Canadian Annamay Pierse in July 2009 at the world championships in Rome.

It was the second world mark to fall on Wednesday night, after Hungarian Daniel Gyurta's record-breaking swim in winning gold in the men's 200m breaststroke.