Defending champions Australia [ Images ] were disqualified after their heat in the men's 4x100 medley relay at the World swimming championships on Sunday.

Officials ruled that there had been a faulty takeover between backstroker Josh Watson and breaststroker Jim Piper at the end of the first leg.

Australia finished first in their heat in a time of three minutes 37.29 seconds after world 200 and 400 freestyle champion Ian Thorpe had swum a strong freestyle length to overhaul France's [ Images ] Frederick Bousquet.

The time would have qualified them as third fastest for the final later on Sunday.

The United States were the fastest qualifiers in a championship record of 3:34.80, with Japan [ Images ] second in 3:37.08. France were third fastest in 3:37.57.

Russia [ Images ], without 50 and 100 freestyle champion Alexander Popov, finished fourth in 3:38.14. opov is expected to race in the final.

World record holder Michael Phelps [ Images ] of the United States qualified second fastest for the men's 400 metres individual medley.

Phelps, the 200 medley and 200 butterfly champion, touched in 4:15.72, well outside his record of 4:10.73, to win the final heat.

Laslzo Cseh of Hungary was the fastest qualifier in 4:14.11 with Japan's Takahiro Mori third fastest in 4:17.12.

Olympic [ Images ] and defending champion Yana Klochkova of the Ukraine was the third fastest qualifier in the women's 400 individual medley in 4:44.14, well outside her world record time of 4:33.59.

Hungary's Eva Ristov, the silver medallist in the 400 freestyle and 200 butterfly, was the fastest qualifier in 4:42.89.

Risztov, 17, finished second behind Klochkova in both individual medley events at last year's European championships.

Nicole Hetzer of Germany [ Images ] was second fastest in 4:43.48, while 2001 bronze medallist Beatrice Caslaru of Romania was fourth in 4:44.26.

The championships finish later on Sunday with seven finals, including the men's 1500 freestyle, both individual medley events and the men's 4x100 medley relay.