BEIJING — Natalie Du Toit of South Africa and Erin Popovich of the United States keep winning swimming gold medals at the Paralympics.

Du Toit, one of two athletes who also competed in the Beijing Olympics, captured her third gold medal of the Paralympics on Thursday, setting a world record for her disability class in the 200-meter individual medley. She finished in 2 minutes, 27.83 seconds, breaking her mark by more than two seconds.

"I think I went out there and just gave everything," said Du Toit, who has two races remaining. "By the end I had nothing."

Du Toit, who lost her leg in a 2001 motorcycle crash, finished 16th in the Beijing Olympics in the 10-kilometer open-water swim.

Popovich, the American team captain, won her fourth Paralympic gold, taking the 400-meter freestyle. She also won gold in the 100 backstroke, 200 individual medley and 100 freestyle, and will try for two more gold medals this weekend.

Popovich won seven gold in Athens, but will be limited to six this time after a relay was cut from the program. She also won three more gold medals in the Sydney Paralympics eight years ago.

"Everyone is capable of doing something, whichever walk of life they come from," Popovich said.

Thirteen medal events were held in swimming, with 11 in table tennis, 10 in track and field. Other medals events included shooting (2), equestrian (3), power lifting (2) and rowing (4).

Britain won two of the four gold medals in rowing with Helene Raynsford taking women's singles sculls and Tom Aggar winning the men's single sculls.

Two power lifters were banned for two years for failing doping tests, bringing to four the number of athletes caught using illegal substances leading to the Beijing Paralympics.

Facourou Sissoko of Mali and Liudmyla Osmanova of Ukraine gave positive tests for steroids in out-of-competition tests, the International Paralympic Committee said Thursday.

Two other athletes already had been sent home for failing pre-games doping tests — German wheelchair basketball player Ahmet Coskun and Pakistani powerlifter Naveed Ahmed Butt.

An Irish soccer player with cerebral palsy was expelled because he was ruled not to be sufficiently disabled. Derek Malone was ruled ineligible for seven-per-team soccer after officials determined he did not show enough impairment.

In a news conference Thursday, Malone said he had trained to limit his impairment and was being penalized for "working hard."