Aung San Suu Kyi's political party is urging Myanmar's people to oppose Monday's coup and any return to military dictatorship.
The National League for Democracy released a statement on the Facebook page of its party head, Suu Kyi, saying the military's actions were unjustified and went against the constitution and the will of voters.
It was not possible to confirm who posted the message as NLD members were not answering phone calls.
Myanmar military television said Monday that the military was taking control of the country for one year, while reports said many of the country's senior politicians including Suu Kyi had been detained.