Bahrain's Olympic 1,500 meters champion Rashid Ramzi has been stripped of his gold medal for doping at the Beijing 2008 Games, a source within the Olympic movement said yesterday.

"Ramzi has been stripped of his gold medal," the source said.

Moroccan-born Ramzi's positive test for the banned blood-booster CERA was announced in April after frozen samples from the Beijing Olympics were re-tested for that specific substance.

Four other Olympic competitors have also been sanctioned after positive doping tests.

The IOC has disqualified these athletes from the Games and has ordered their federations to adjust the final standings in their events and take further action regarding their bans, the Greek Olympic Committee confirmed in a statement.

First-time offenders face an automatic two-year suspension while repeat offenders could be banned for life.

Under International Olympic Committee rules anyone handed a six-month suspension or longer is also banned from competing in the 2012 Games in London.

Asbel Kipruto Kiprop of Kenya who won silver behind Ramzi now stands to be upgraded to gold, with the decision resting on the IOC.

New Zealand's Nicholas Willis took bronze in the 1,500 final and Mehdi Baala of France was fourth.

Italy's cycling road race silver medallist Davide Rebellin was ordered to return his medal by Italy's Olympic Committee on Tuesday.

Apart from Ramzi and Rebellin, German cyclist Stefan Schumacher, already banned for doping, was also confirmed positive as were Greece's 2004 Athens Games 20km walk champion Athanasia Tsoumeleka and Croatian 800 meters runner Vanja Perisic.

The athletes all had tested positive for CERA, the new generation of erythropoietin (EPO).

The IOC retested 948 athletes' samples, focusing mainly on endurance events in cycling, rowing, swimming and athletics.

Six athletes had initially tested positive after Beijing blood sample retests were conducted months after the Games.

Dominican Republic weightlifter Yudelquis Contreras was cleared after her B sample came back negative. Nine other athletes tested positive in tests conducted during the Games as well as six horses in the equestrian events.

The IOC conducted the largest ever doping operation with about 5,000 blood and urine tests during the Beijing Games.