The US quartet of Ryan Murphy, Kevin Cordes, Kelsei Worrell and Mallory Comerford clocked 3mins 40.28secs to break the previous record of 3:41.71 set by Great Britain two years ago in Kazan.

This is only the second world championships were the mixed 4x100m medley relay has been added to the schedule.

The record is in danger of falling again in Wednesday night's final with Australia, Great Britain and Canada all qualifying behind the USA.

This is the sixth time a world record has been broken at these world championships.

Britain's Adam Peaty lowered his own 50m breaststroke record twice on Tuesday and it could fall again in Wednesday night's final.