ROME (AP) _ Rome prosecutors formally opened a criminal investigation into allegations of doping against Ivan Basso on Thursday, three days after the Giro d'Italia champion admitted involvement in the Spanish doping scandal.

Basso is being investigated for the alleged use of a banned substance or method, the ANSA and Apcom agencies said.

Doping is a criminal offence in Italy and carries a maximum penalty of two years in jail _ although prison sentences of a couple of years are routinely suspended for first offenders.

Basso told the Italian Olympic Committee on Monday that he had given blood samples to a Spanish doctor, Eufemiano Fuentes, who has been accused of running a blood-doping clinic in Madrid.

The 29-year-old Basso said he had intended to cheat but never did.

Also Thursday, Basso reportedly had another session before the committee to clarify certain aspects of his testimony. He was charged by CONI with using or attempting to use a banned substance or method last week.

Michele Scarponi also admitted involvement in the scandal on Tuesday and denies doping.

The names of both Italians turned up on a list of riders who allegedly had contact with Fuentes.

Basso and Scarponi risk a two-year ban from cycling. Neither rider will compete in the Giro, which begins Saturday.