KUALA LUMPUR, Malaysia — Runners carried the Olympic torch through Malaysia's capital today after police detained a Japanese family carrying a pro-Tibet banner and took a Buddhist monk into custody as a "preventive" measure.

There was no immediate information that the monk, whose nationality was not known, had done anything wrong, said Kuala Lampur police chief Muhammad Sabtu Osman. The monk was detained on the route as a "preventive" measure, the police chief said, without elaborating.

The Japanese family of three unfurled a pro-Tibet banner about an hour before the president of the Olympic Council of Malaysia, Imran Jaafar, set off with the torch. Jaafar was the first of 80 runners who planned carry it through the capital.

Witnesses said the adult couple and a boy were heckled by bystanders, who appeared to be Chinese, during the confrontation, which occurred at Independence Square where the 10-mile relay began.

Thousands of bystanders — many of them wearing red — were gathered to watch the send-off. Some carried Chinese flags and Chinese language banners that read: "The Torch will spread around the world," and "No one can split China."

The witnesses said some of the bystanders shouted "Taiwan and Tibet belong to China" when they saw the family revealing the pro-Tibet banner. The witnesses couldn't recall the exact wording on the banner because of the commotion. They all declined to be named, citing reluctance to be associated with a foreign media organization or to be involved in a police matter.

Muhammad Sabtu said the Japanese were held after they waved a Tibetan flag. He did not mention the banner.

He said they were detained "only for documentation," and said he had no information that they were beaten by other crowd members, as some witnesses reported.

Criticism of China's human rights record has turned the Olympics into one of the most contentious in recent history.

Protests have dogged the torch relay during its stops in Paris, London and San Francisco, with demonstrations over China's crackdown in Tibet where it forcefully put down anti-government riots.

Fear of further disruptions has triggered an unprecedented security presence for the Malaysian leg. Some 1,000 policemen and commandos were deployed in along the route in Kuala Lumpur even though police have not received reports of any planned protests, said a police spokesman who declined to be named, citing protocol.

The flame arrived Sunday from Bangkok, where its relay was unmarred by demonstrations.