GOTHENBURG, Sweden - The president of the International Association of Athletics Federations (IAAF) wants athletes who test positive for substances such as steroids to be banned for four years.

"We want to move towards four-year bans," Lamine Diack told reporters on Sunday in Gothenburg, where the European athletics championships start on Monday.

"We cannot accept any doubts about the performances of our athletes."

Diack's proposal came a few days after Olympic and world 100 metres champion Justin Gatlin said he had tested positive for testosterone, dealing a serious blow to the showcase Olympic sport.

Under the current rules of the World Anti-Doping Agency (WADA), athletes face a two-year suspension for a first doping offence and a life ban in case of a second.

The four-year bans would apply for positive tests for only some performance-enhancing drugs including steroids and erythropoietin (EPO), Diack said.

The four-year ban proposal would be on the agenda of the ruling body's next congress in August 2007 in Osaka, Japan, he added.

Diack said he would try to convince other federations to follow suit and hoped WADA would promote four-year bans at its next congress scheduled for November 2007.

The IAAF used to inflict four-year bans for steroid offences but dropped the sanction to two years in 1997 after courts in some countries refused to uphold the longer penalty.

"We know there could be some difficult situations but that's the way we want to go," Diack said when asked whether the reinstatement of four-year bans could result in more legal battles for IAAF.

Gatlin, joint world 100 metres record holder with Jamaican Asafa Powell, will attend a hearing before the US Anti-Doping Agency (USADA) in the near future.

The 24-year-old American has denied ever knowingly using a banned substance or authorising anyone else to administer one to him.

"This is a disaster for our sport," Diack said of Gatlin's positive test.

"I was convinced he was a great champion and he actually played an important role in USADA's campaign against doping.

"This is bad publicity. At last year's world championships we believed a new generation was coming up and we were moving out of all this. Sadly, it is not the case."

More than half a dozen athletes currently or previously trained by Gatlin's coach, Trevor Graham, including disgraced former 100 metres world record-holder Tim Montgomery, have been suspended for doping.

"It is disturbing that so many of Trevor Graham's athletes have tested positive," Diack said.

The IAAF president, however, ruled out immediate sanctions from the ruling body against the coach, who has been banned by the US Olympic Committee (USOC) from using their training centres and facilities.

"This is a difficult situation but we must face it", Diack said of the turbulent climate created by the Gatlin case.

"Our society is such that there will always be cheats but they must know that we will do everything in our power to get rid of them."