World MotoGP champion Valentino Rossi has reportedly gone into hiding in Italy after being named in a letter from a terrorist organisation.
According to Italian media reports, a letter bomb was sent to the Milan offices of Iberian airlines warning the Repsol Honda rider to sever all connections with Spanish oil group Repsol-YPF.
The communication was said to have been sent by an anarchist group believed to behind a spate of letter bombs in Spain and Italy.
Rossi is based in London but has returned to Italy for an awards ceremony.
A spokesman for Rossi's Honda team said that the world champion had only heard of the threat from media reports and had been shocked by the news.
Rossi completely dominated the first season of MotoGP, taking the title after winning 11 races.
The 23-year-old has won 50 of the 108 grands prix he has ridden in.