LONDON - Two athletes saw their Olympic hopes cut short on Sunday after being suspended from the London 2012 Games for using banned performance-enhancing drugs, taking the tally of doping offenders after two days of competition to three.

With the International Olympic Committee eager to root out doping at the Games, testers have been out in force, conducting random and target testing for months to ensure the July 27-Aug 12 event will not be tarnished by any high profile cases.

St Kitts and Nevis sprinter Tameka Williams became the latest casualty on Sunday after admitting to team officials she had used a banned substance and being sent home days before she was due to compete.

The country's Olympic Committee said the 22-year-old, who was due to race in the 100 and 200 meters at her first Games, had voluntarily provided the information which could see her getting a reduced sentence or even escape punishment altogether depending on the circumstances.

"In discussion with team management, Ms Williams volunteered information to the effect that she has been using a substance which the SKNOC considers to fall outside the internationally accepted medical code," the country's Olympic Committee said.

The committee, which has informed all relevant bodies and also launched an investigation, did not provide any details on the drug in question or the circumstances under which the athlete took it.

Masking agent

Earlier on Sunday, Uzbekistan's only gymnast at the Games, Luiza Galiulina, was temporarily suspended after her first sample came in positive for the drug Furosemide, often used as a masking agent for other banned substances.

The 20-year-old Galiulina, who had been due to compete later on Sunday only in the floor exercise, will now have to wait for the testing of a second sample.

Should that also come in positive, she would be barred from competing in London and could face a maximum two-year ban as a first-time doping offender.

Furosemide, often sold under the brand name Lasix, can be used to treat high blood pressure, congestive heart failure or swelling caused by excess fluid retention.

Over the course of the London Games, the IOC has said it expects to carry out some 5,000 tests - 3,800 urine and 1,200 blood.

A drive by anti-doping agencies across the world yielded more than 100 cheaters ahead of the Games as the IOC seeks to avoid major doping scandals that hit previous editions of the multi-billion dollar event and overshadowed the competitions.

The first drugs cheat was caught on Saturday, hours after the opening ceremony, with Albanian weightlifter Hysen Pulaku ejected for using an anabolic steroid.

The 19-year-old, who was due to compete in the men's 77kg class, tested positive to Stanozolol and now faces a two-year suspension.

Any sanctions or suspensions are issued by the athletes' respective sports federations.

The IOC's zero tolerance on drugs in not only aimed at staging clean Games but also at protecting its lucrative brand and shielding sponsors and broadcasters who pay hundreds of millions of dollars to be associated with the Olympics.

There were 20 proven cases of doping at the Beijing Games four years ago, including six horses, down from 26 cases in Athens in 2004.