World road champion Paolo Bettini was interviewed by police in Stuttgart on Thursday as he prepares to defend his title in Sunday's elite men's road race.

The 33-year-old was questioned on Thursday afternoon, according to International Cycling Union (UCI) spokesman Enrico Carpani, but no other details were available.

On Wednesday, Olympic and world cycling champion Bettini was accused by sacked cyclist Patrik Sinkewitz of supplying the German with doping products. Sinkewitz, 26, was dismissed by T-Mobile during this year's Tour de France when abnormal levels of testosterone were found in his blood during a pre-race drugs test.

And on Thursday morning, the world champs' organising committee filed a provisional order at Stuttgart's regional court to prevent Bettini from starting Sunday's race. The organisers insist Bettini signs the full UCI anti-doping agreement which makes it compulsory for every rider to provide a blood sample before Sunday's race.

Bettini says demanding a sample is a breach of his human rights and has also refused to sign any agreement because of a clause which demands the repayment of a year's salary after a positive drugs test.

Susanne Eisenmann, the president of the organising committee in Stuttgart, told German television channel ZDF on Thursday morning she wants every rider to sign the agreement to ensure the event is as drugs-free as possible.

But UCI president Pat McQuaid insisted the organisers did not have the right to prevent Bettini competing in Stuttgart. "The signing of the agreement is only a moral obligation, that is something the Stuttgart organisers must accept," said McQuaid.

Eisenmann met journalists at Stuttgart's world championships this morning and underlined her determination to have Bettini sign the full agreement.

The Italian signed a partial agreement in July which excluded the providing of a blood sample. "The court is checking whether the document signed in July is legally binding," said Eisenmann. "If that is the case, we will then have the legal power to say to the UCI that Bettini does not have the right to compete."

The court's decision is expected on Friday.

To add to the tension, the relationship between the Stuttgart organisers of the World Road Championships and the German Cycling Federation (BDR) has become frosty.

BDR vice-president Udo Sprenger has been made a "persona non-gratis" by the organisers who want Sprenger to leave the championships and have his accreditation removed, said Eisenmann. Sprenger was accused last June of being involved in doping by an anonymous source.

BDR president Rudolf Scharping had backed Sprenger, who filed a slander complaint against the allegation. But Eisenmann insists the source is creditable and reliable.