The United States retained both Olympic 4x400 metres relay titles on Saturday with individual champion Jeremy Wariner running the third leg for the men's team.

The Americans were already well in front when Wariner received the baton and he in turn gave Darold Williamson a clear lead.

Williamson completed victory for the United States in two minutes 55.91 seconds with Australia second almost five seconds back and Nigeria third.

None of the American team were in the squad who competed in Sydney four years and who are now certain to lose their gold medals.

The world governing body has annulled the results and recommended that the International Olympic Committee (IOC) take back the medals because one of the American team, world 400 metres champion Jerome Young, should have been serving a doping ban.

The U.S. women's squad recorded a commanding victory over their traditional rivals Russia with Monique Hennagan running the final leg for the Americans after DeeDee Trotter, Monique Henderson and Sanya Richards had completed the early laps.

They clocked three minutes 19.01 seconds with Russia second and Jamaica third.

Four years ago at the Sydney Games, Marion Jones won her third gold and fifth medal overall in the 4x400. She was not included this time and left the Athens Games on Friday without a single medal.