He now faces a likely two-year ban that would bar him from this month's World Championships in Seville, Spain, and next year's Sydney Olympics.

The BBC's Tom Gibb: "It's thought the cocaine may have been in medicine for back pain"

The scandal is the third doping violation to rock the athletics world in two days.

The announcement came just hours after news that British sprint champion Linford Christie had been suspended from athletics after failing a drugs test.

Sotomayor became the first athletics competitor to win individual gold medals at four consecutive Pan Am Games after clearing 2.30 metres on Friday.

His test results were announced by the president of the Pan American Sports Organization (Paso), Mario Vasques Rana, on Wednesday.

Mr Vasques Rana said Paso did not differentiate between a recreational drug such as cocaine and a performance-enhancing substance such as a steroid.

Sotomayor had complained of back pains during the games and the Cuban delegation has suggested the cocaine could have been in a medicine.

Stunned

The president of the International Amateur Athletic Federation (IAAF), Primo Nebiolo, said he was stunned by the test announcement.

The news has not been reported in Cuba

"I am shocked. I cannot believe it. I am very surprised and upset, because I have great esteem for Sotomayor," he added.

Sotomayor, 31, is regarded as one of athletics' greats. He won the world title in 1997 and took the Olympic crown in 1992.

He also won gold at the 1993 world championships and took silver in the 1991 and 1995 events.

He was ranked number one in the world in 1988-89, 1992-95 and 1997-98. His world record stands at 2.45m.

Three stripped of gold

The doping scandal comes a day after Dennis Mitchell, the US 100m champion and 1992 Olympic bronze medalist, was banned for two years by the IAAF after a doping test showed high levels of testosterone.

Sotomayor is the third gold medalist athlete to test positive for banned substances at the Pan Am Games.

Steve Vezina, Canada's roller hockey goalie, tested positive for nandrolone. and women's high jumper Juana Arrendel was stripped of her medal after testing positive for stanozolol.