© AFPAn injured protester lies on a stretcher after Yangon protest.
Witnesses at the scene said dozens had been injured. Photos and videos on social media show a vehicle that crashed through the protesters and bodies lying in the road.
Another protest was held in Yangon in the afternoon despite the morning's violence.
Anti-military protests are continuing despite the killing of more than 1,300 people since the February 1 coup. The scattered protests are often small groups voicing opposition to the overthrow of an elected government led by Nobel laureate Aung San Suu Kyi and the return of military rule.
© AFPProtesters march during a rally against the military coup in Yangon on December 5, 2021.
"We will strongly respond to the terrorist military who brutally, inhumanly killed the unarmed peaceful protesters," the National Unity Government's defence ministry said in a statement on social media after Sunday's attack.
In the incident, a "flash mob" protest in Yangon, Myanmar's largest city, was rammed minutes after it started, witnesses said.
"I got hit and fell down in front of a truck. A soldier beat me with his rifle but I defended and pushed him back. Then he immediately shot at me as I ran away in a zigzag pattern. Fortunately, I escaped," a protester said, who asked not to be identified for security reasons.
A car occupied by soldiers hit the crowd from the back, two witnesses said, and followed the scattered protesters arresting and beating them. Some were seriously injured with head wounds and unconscious, according to the witnesses.
© AFPA protester, kneels on the ground beside a soldier after Yangon protest.
The military has said that protesters who have been killed instigated the violence. It says it staged the coup because a November election won by Suu Kyi's party was rigged. The election commission has dismissed the assertion.
Wars with ethnic minority insurgents in remote frontier regions in the north and east have intensified significantly since the coup, displacing tens of thousands of civilians, according to United Nations estimates.
Suu Kyi, 76, faces a dozen cases against her including incitement and violations of Covid-19 protocols. She has rejected all the charges to date.
What is happening is the replay of decades ago with a new generation. As an older person who has watched the world endure US military incursions that create a devastated economy and result in yet another country being added to the global remittances count, sense we have reached the point of no return in corporate control.