The United States was on Saturday finally stripped of the men's 4x400 metres relay gold medal from the 2000 Olympics in the wake of doping confessions by relay team member Antonio Pettigrew.

The International Olympic Committee (IOC) executive board made the decision at meetings ahead of the Beijing Games, but did not immediately re-allocate the medals.

Pettigrew, who was in the Sydney 2000 relay along with Michael Johnson and the Harrison brothers Alvin and Calvin, recently admitted to have used forbidden substances from 1997 onwards.

IOC spokeswoman Giselle Davies said the re-allocation of the medals will take place "in due course," adding that the issue was part of "a thorough piece of work."

The IOC is still looking into the BALCO laboratory case after Marion Jones admitted to doping in Sydney as well, using forbidden substances supplied by the lab. She won three gold and two bronze medals in Sydney.

The IOC faces a delicate challenge over the medals as the 100m second-place finisher is Katerina Thanou of Greece, who herself was caught in a massive doping scandal at the 2004 Games and whose eligibility to compete in Beijing is to be reviewed on Thursday by the IOC.

The men's 4x400m relay was already due to be stripped of the medals a few years ago after Kevin Young, who ran in the heats, was punished over a doping offence. But the ruling body IAAF was unable to retroactively strip an entire team of medals due to its rules at the time