Nationwide "silent strike" comes after deposed leader Aung San Suu Kyi was sentenced to four years in prison.
Protesters in Myanmar have closed businesses and stayed off the streets in a "silent strike" against rule by the military and its ousting of country's democratically elected government in a February coup.
Photos published by Myanmar media on Friday showed deserted streets and markets in towns across the country, while protesters in the northern city of Shwebo wore black clothes and marched in silence.
"We need to send a message to the world about Myanmar's terrible human rights violations," protest leader Khin Sandar told media.
"Silence is the loudest shout. We want our rights back. We want revolution. We express sadness for our fallen heroes," she said.
Deposed leader Aung San Suu Kyi, 76, is facing various charges and was sentenced to four years in prison on Monday on the first of them – incitement and breaching coronavirus regulations – drawing international condemnation of what critics described as a "sham trial".
The junta chief later reduced her sentence by two years on "grounds of humanity" but the charges she still faces could see her jailed for many years.
Junta forces seeking to crush opposition have killed more than 1,300 people, according to the Assistance Association for Political Prisoners monitoring group.
Last Sunday, five people were killed and at least 15 arrested after soldiers used a car to crash through an anti-coup protest in the city of Yangon. Myanmar's state media has dismissed reports of the incident as disinformation.
Minn Khant Kyaw Linn, a student activist from the General Strikes Collaboration Body protest group said participation in the "silent strike" had been widespread.
"You can see how much people hate the junta," he said.