The former world 1500m champion Abeba Aregawi has tested positive for a banned substance. The news was confirmed by the sport’s governing body, the IAAF, and the Swedish Athletics Federation, who said the 25-year-old had withdrawn from competition following an out-of-competition urine test, believed to be in Addis Adaba in January.

An IAAF spokesman said: “Following notification of the laboratory finding, the athlete has voluntarily withdrawn from competition until the investigations into the laboratory finding are completed. In the meantime, the athlete has requested the analysis of the B sample which will be conducted shortly.

“The IAAF and the Swedish Athletic Federation will not make any further comment until completion of the result management procedure.”

Rumours had been swirling around the sport for several weeks that the Ethiopian-born Aregawi, who has competed for Sweden since 2012, had tested positive. However, it is unusual for a failed athlete’s test to be announced before the B sample has been conducted.

Aregawi, who is also the reigning world indoor 1500m champion and European championship silver medallist, was due to face the world record holder Genzebe Dibaba in a much anticipated race over a mile in Stockholm on 17 February, but pulled out citing a back injury. There were whispers then that the reason was more serious.

There are also strong indications that Aregawi is one of a number of Ethiopian-born athletes who will be announced to have failed drugs tests in the coming weeks.

The Swedish newspaper Aftonbladet, which broke the Aregawi story, quoted the Swedish Athletics general secretary, Stefan Ollson, who said: “We are totally opposed to all forms of cheating, doping and illicit funds. We have a zero tolerance, and this is totally unacceptable.”

Aregawi won gold at the 2013 World Championships in Moscow, when she ran 4:02.67 to win the 1500m final – a race in which Britain’s Hannah England finished fourth. She was sixth at the world championships in Beijing last August.

The news comes just days after the Swedish newspaper Sports Expressen revealed that Aregawi had been caught in a storm over unpaid taxes after telling Swedish authorities she had never lived in the country and so was not liable for tax.

Citing documentary evidence from the tax authorities, the paper said that Aregawi had confessed that she had never been resident in Sweden, and that she submitted false information to the Immigration Service when she applied for Swedish citizenship. Aregawi was ordered to pay 11,112 Swedish crowns (£932) in back taxes,

Two years ago Aregawi also had to defend herself against allegations that she had deliberately entered a ‘sham’ marriage with Swedish husband Henok Weldegebriel, who she divorced shortly afterwards, in order to get citizenship.