Myanmar’s military has seized power after detaining Aung San Suu Kyi and other democratically elected leaders.
Troops are patrolling the streets and a night-time curfew is in force, with a one-year state of emergency declared.
US President Joe Biden raised the threat of new sanctions, with the UN and UK also condemning the coup.
The army alleges the recent landslide election win by Ms Suu Kyi’s party was marred by fraud. She urged supporters to “protest against the coup”.
In a letter written in preparation for her impending detention, she said the military’s actions would put the country back under a dictatorship.
The military has already announced replacements for a number of ministers.
On the streets of the main city, Yangon (Rangoon), people showed their disappointment as they felt their hard-fought battle for democracy had been lost.
One 25-year-old resident, who asked not to be named, reported to BBC: “Waking up to learn your world has been completely turned upside down overnight was not a new feeling, but a feeling that I thought that we had moved on from, and one that I never thought we’d be forced to feel again.”
Myanmar, also known as Burma, was ruled by the armed forces from 1962 until 2011 when a new government began ushering in a return to civilian rule.
She spent nearly 15 years in detention between 1989 and 2010. She was internationally hailed as a beacon of democracy and received the Nobel Peace Prize in 1991.
But her international reputation suffered severely following an army crackdown on the mostly Muslim Rohingya minority. Former supporters accused her of refusing to condemn the military or acknowledge accounts of atrocities.
How did the coup unfold?
In the early hours of Monday, the army’s TV station said power had been taken over by commander-in-chief Min Aung Hlaing.
Ms Suu Kyi, President Win Myint and other leaders of the National League for Democracy (NLD) were arrested in a series of raids. It is not clear where they are being held.
No major violence has been reported. Soldiers blocked roads in the capital, Nay Pyi Taw, and the main city, Yangon. International and domestic TV channels, including the state broadcaster, went off air. Internet and phone were disrupted. Banks said they had been forced to close.
Later, the military announced that 24 ministers and deputies had been removed, and 11 replacements had been named, including in finance, health, the interior and foreign affairs.
A curfew is now reportedly in effect from 20:00 local time to 06:00 (13:30-23:30 GMT).