The United States has threatened sanction against the country as the United Nations condemned the coup.
In an early morning raid, Suu Kyi was detained along with other leaders of her National League for Democracy (NLD) party.
The army said it had carried out the detentions in response to “election fraud”, handing power to military chief Min Aung Hlaing and imposing a state of emergency for one year, according to a statement on a military-owned television station.
The generals made their move hours before parliament had been due to sit for the first time since the NLD’s landslide win in a Nov. 8 election viewed as a referendum on Suu Kyi’s fledgling democratic government.
Phone lines to the capital Naypyitaw and the main commercial centre of Yangon were not reachable, and state TV went off air. People rushed to markets in Yangon to stock up on food and supplies while others lined up at ATMs to withdraw cash.
Soldiers took up positions at city hall in Yangon and mobile internet data and phone services in the NLD stronghold were disrupted, residents said. Internet connectivity also had fallen dramatically, monitoring service NetBlocks said.