LONDON -- Track and field's world governing body plans to punish any coaches directly connected to the spate of positive tests among U.S. athletes for the stimulant modafinil.

Six Americans have been identified as testing positive for the substance, which is prescribed for treatment of the sleeping disorder narcolepsy.

Istvan Gyulai, general secretary of the International Association of Athletics Federations, said Tuesday that any coaches or trainers involved in the use of modafinil should face sanctions.

"If it proved that they incite or promote the use of drugs or substances which are not permitted, they are considered to have committed a doping offense themselves," he told The Associated Press in a telephone interview.

"This has to be investigated," Gyulai added. "We cannot just turn a blind eye to this."

IAAF rules do not specify penalties for non-athletes in doping cases. But Gyulai said the IAAF could consider banning a coach or refusing accreditation for major events.

Three more U.S. athletes were cited in newspaper reports Tuesday for positive modafinil tests.

The Washington Post, citing unidentified sources, reported that sprinter Chryste Gaines -- a relay gold medalist at the 1996 Olympics --tested positive at the U.S. championships in Stanford, Calif., in July.

The Los Angeles Times, citing unnamed sources, said hurdlers Sandra Glover and Eric Thomas also tested positive for the drug.

Calvin Harrison, an Olympic and world relay gold medalist, had previously confirmed he tested positive for modafinil at the U.S. meet.

Sprinter Kelli White and hurdler Chris Phillips tested positive at the World Championships. White, who said she took modafinil for narcolepsy, risks losing her gold medals from the 100 and 200 meters.

Modafinil wasn't named on the sport's banned drug list, but the IAAF said it fell under the category of related substances and classified as a "minor stimulant." It has since been placed by name on the World Anti-Doping Agency's banned list.

Gyulai said it's possible the athletes all believed modafinil wasn't prohibited.

"This is an option, but it has been determined that it is a stimulant and was a stimulant at the time as well," he said. "It's up to USA Track & Field to take the necessary action."

The IAAF's penalty for use of minor stimulants is a public warning and disqualification from the event where the test took place -- but no ban.

Some of the athletes have been coached by Ukrainian-born coach Remi Korchemny, who is based in the San Francisco area. He did not return repeated messages left by the AP this week.

Robert Wagner, the agent for White, Phillips and Glover, said Phillips told the IAAF that Korchemny gave him a modafinil tablet at the worlds because he was having trouble sleeping.

"None of these athletes thought this was a prohibited substance, they were taking it all summer," Wagner told the AP by telephone from Austria. "It's like melatonin. When Americans come to Europe, they take it to get over the jet lag. It's not a stimulant. It wasn't on the list."

Gyulai stressed that modafinil should not be viewed in the same light as the designer steroid THG, which has turned up in the samples of several track and field athletes. The sanction for steroids is a two-year ban.

"THG was invented, produced and masterminded to cheat," Gyulai said. "There is a major difference with modafinil. The athletes may have thought this is not forbidden. They should have checked more carefully."

Gyulai said he had read or heard reports of a total of seven modafinil cases, but stressed the IAAF had received no official notification of the tests or names involved.