Two people reportedly died of gunshot wounds sustained as security forces tried to disperse anti-coup protesters in the city of Mandalay on Wednesday.
Multiple reports from several other cities and towns in Myanmar also said police also used live ammunition, as well as tear gas and rubber bullets.
Reports of fatalities elsewhere
There were reports that four people were shot dead in the country's Sagaing region.
At least one person was reported to have been killed in the largest city of Yangon.
Two protesters were believed to have been killed and others injured in the central town of Myingyan.
"They opened fire on us with live bullets. One was killed, he's young, a teenage boy, shot in the head," student activist Moe Myint Hein, who was wounded in the leg, told Reuters by telephone from Myingyan.
The country has faced chaos since February 1 when the military staged a coup and arrested de facto civilian leader Aung San Suu Kyi.
The coup brought to a halt Myanmar's decade-long experiment with more democratic governance and sparked daily mass protests.
The military regime in Myanmar on Tuesday said it had suspended its envoy to the United Nations, the Aung San Suu Kyi-appointed Kyaw Moe Tun. However, Tun has contradicted this, saying he should stay in post.