BANGKOK/MELBOURNE: Sean Turnell, an Australian economic adviser to Myanmar's Aung San Suu Kyi, said in a message to Reuters on Saturday he was being detained, days after she was overthrown in a coup.
"I guess you will soon hear of it, but I am being detained," he said.
"Being charged with something, but not sure what. I am fine and strong, and not guilty of anything," he said, with a smile emoji.
It was not subsequently possible to contact him.
This is the first known arrest of a foreign national in Myanmar since the army generals seized power alleging fraud in a Nov 8 election that Suu Kyi's National League for Democracy (NLD) won in a landslide.
Australia's foreign ministry was not immediately available to comment.
Mr Turnell is a professor of economics at Macquarie University in Sydney and has been advising Suu Kyi on economic policy for several years.
On Saturday, several thousand protesters gathered in Australia's second-largest city of Melbourne denouncing the coup and demanding the release of Suu Kyi.
Television and social media footage showed people wearing the red colour of the NLD, carrying portraits of Suu Kyi and singing We Won't Be Satisfied Until The End Of The World, the Burmese language anthem from the country’s 1988 pro-democracy uprising, brutally put down by the military government.