The fresh rally followed the largest protests to date on Saturday, when tens of thousands came out in cities across the country to condemn the coup that brought a 10-year experiment with democracy to a crashing halt.
Thousands of chanting protesters marched in Yangon, backed by a din of car horns. They held up banners - including some saying "We do not want military dictatorship" - and the signature red flags of Aung San Suu Kyi's National League of Democracy (NLD) party.
"I completely despise the military coup and I am not afraid of a crackdown," said Kyi Phyu Kyaw, a 20-year-old university student.
"I will join every day until Amay Suu (Mother Suu) is freed."
Many demonstrators flashed the three-finger salute inspired by the Hunger Games films, which was used as a symbol of resistance by protesters in Thailand last year.
The protesters planned to hold a rally at Yangon City Hall, but access to the area was blocked by police and barricades. Demonstrators were forced to split into different groups as they tried to find a way around the checkpoints.
"We have decided. We will fight until the end," said Ye Kyaw, an 18-year-old economics student.
"The next generation can have democracy if we end this military dictatorship."
The surge in popular dissent over the weekend overrode a nationwide blockade of the Internet, similar in magnitude to an earlier shutdown that coincided with the arrest of Aung San Suu Kyi and other senior leaders on Monday.
Online calls to protest the army takeover have prompted bold displays of defiance, including the nightly deafening clamour of people around the country banging pots and pans - a practice traditionally associated with driving out evil spirits.
Yangon residents repeated the pot-banging at 8am on Sunday.
"#Myanmar's military and police must ensure the right to peaceful assembly is fully respected and demonstrators are not subjected to reprisals," the United Nations Human Rights office tweeted after Saturday's protests.
As protests gathered steam this week, the junta ordered telecom networks to freeze access to Facebook, an extremely popular service in the country and arguably its main mode of communication.
The platform had hosted a rapidly growing "Civil Disobedience Movement" forum that had inspired civil servants, healthcare professionals, and teachers to show their dissent by boycotting their jobs.
On Sunday, a live Facebook video feed showed the Yangon protesters as they marched through the streets, as well as police in riot personnel standing by in some locations.
It was not immediately clear how the broadcast was bypassing the government block.
The military had widened its efforts to quell organised dissent on Friday when it demanded new blocks on other social media services including Twitter.
"The generals are now attempting to paralyse the citizen movement of resistance - and keep the outside world in the dark - by cutting virtually all Internet access," said Tom Andrews, UN special rapporteur on human rights in Myanmar.
In addition to Aung San Suu Kyi and some of her top aides, dozens have been detained so far.
The precise number of arrests is not yet known, but monitoring group Assistance Association for Political Prisoners said Saturday that more than 150 people are still in custody.
Rumours that Aung San Suu Kyi had been released triggered brief but raucous street celebrations among her supporters on Saturday, before they were denied by her lawyer who said she remained in detention.
An immensely popular figure despite a tarnished reputation in the West, Aung San Suu Kyi has not been seen in public since the coup, but a party spokesman said Friday she was under house arrest and "in good health".
Two days after the coup, criminal charges were filed against her related to the illegal import of a set of walkie-talkies.
The military had hinted at its coup intentions days in advance, insisting that the NLD's landslide victory in the November elections was the result of voter fraud.
The Union Solidarity and Development Party, a military proxy, was trounced in the election.
Following the takeover, the junta proclaimed a one-year state of emergency after which it promised to hold fresh elections, without offering any precise timeframe.
The coup has been widely condemned by the international community, with US President Joe Biden leading calls for the generals to relinquish power and release those arrested in the post-coup crackdown.