Protesters hurled rubbish at the Beijing Olympic torch and brawled with Chinese supporters in a chaotic Japanese leg of the worldwide relay that left at least four people injured.

Thousands of Chinese students flocked to the mountain town of Nagano, turning the streets into a sea of red national flags as thousands of police kept guard while the relay was run.

But hundreds of demonstrators also came out in force, ranging from Tibet supporters to members of Japanese nationalist groups, some of whom waved an old imperial flag and held up signs reading, "Shame on China!"