Crowds of Chinese students waving red flags scuffled with pro-Tibet protesters and Japanese nationalists in Saturday's leg of the Olympic torch relay.
The global torch relay ahead of the Beijing Games in August has prompted protests against China's human rights record as well as patriotic rallies by Chinese who criticise the West for vilifying Beijing.
As rain fell in Nagano, chants of "Go China" mixed with "Free Tibet" from the rival groups, who clashed at times despite tight security in the central city, host to the 1998 Winter Olympics.
Four Chinese supporters were injured and five men were arrested, fire officials and police said, including one man who was wrestled to the ground after running into the relay path holding a Tibetan flag and shouting "Free Tibet".
More than 3,000 police were mobilised for the relay, which comes a day after China's Xinhua news agency said Beijing would hold talks with representatives of the Dalai Lama, the exiled Buddhist leader of Tibet, whom it blames for recent unrest.
Other arms of China's state media, however, kept up their condemnation on Saturday of the Dalai Lama, who fled into exile in India in 1959 after a failed uprising against Communist rule.
Japan, whose ties with Beijing are often tense due to Chinese bitter memories of the wartime past, was keen to avoid the chaotic scenes that marred some of the relay venues elsewhere ahead of next month's high-profile visit by President Hu Jintao.
"I ran hoping for the Beijing Olympics to be successful and peaceful," said Japanese Olympic gold medallist marathon runner Mizuki Noguchi, after lighting the flame on the podium at the end of the relay.
CHINA-TIBET TALKS
Commenting on the turmoil that has bedevilled the global relay, International Olympics Committee (IOC) President Jacques Rogge urged the West to stop hectoring China over human rights.
