The country has been in turmoil since the military ousted civilian leader Aung San Suu Kyi on February 1, bringing an abrupt end to Myanmar's short-lived experiment with democracy.
The power grab triggered a massive uprising which authorities have tried to quell with lethal force and live ammunition.
As Myanmar entered its fourth month under military rule on Saturday, protesters in the commercial hub Yangon, an epicentre of unrest with a heavy security presence, staged flash demonstrations, marching rapidly through the streets to avoid confrontation with police and soldiers.
The lightning-quick pace of the protests is "so that people will have time to disappear when the security forces come, or else they would die or get arrested", said student activist Min Han Htet.
In Yangon's Insein township, a bomb blast went off around 10 am near a local school, said a resident staying nearby.
"Some security forces came to check the blast area, but I only watched from a distance from my home because I was worried they would arrest me," he told AFP.
By afternoon, two more blasts went off in Yankin, further south, according to residents of the leafy residential township.
"I thought it was thunder," a resident told AFP, adding that the explosions left the security forces nervous.
The state-run evening news said a woman was wounded in the Yankin blasts, which it blamed on "instigators".
No one has yet claimed responsibility for the bombings that are taking place with increasing frequency in Yangon.