They said the 1991 Nobel peace prize winner was stopped close to the village Anyarsu, west of Yangon.

Earlier, Myanmar Opposition leader Aung San Suu Kyi defied the military government today by leaving her home here to visit supporters outside the capital.

Officials said that Suu Kyi was stopped near the same point on a similar trip in late July. Anyarsu is west of Yangon and close to a bridge which was the site of a six-day stand-off between Suu Kyi and security men last month.

Suu Kyi became severely dehydrated on that trip and spent several days recuperating in her Yangon home. She had promised to venture out again when she was fully recovered.

Government sources said Suu Kyi was travelling today towards Pathein township, about 190 km west of Yangon. Sources close to her National League for Democracyparty said Suu Kyi was driving with the same companions she had on her July venture -- two drivers and one NLD official.

Meanwhile, the United States today demanded Myanmar's junta immediately release six Americans detained in Yangon for allegedly inciting unrest, a US embassy official said.

``We are now asking for prompt resolution and release of those detained,'' the official said.