Myanmar police fired rubber bullets at demonstrators in the capital Nay Pyi Taw, as thousands defied a ban on protests. Water cannon and tear gas were also used against protesters.
One woman is in hospital in a critical condition with a head wound.
Protesters are fighting against a military coup that removed the elected government last week.
Military leader Min Aung Hlaing has banned large public gatherings and imposed a night-time curfews in some cities.
The demonstrators have been demanding the release of elected leader Aung San Suu Kyi, along with senior leaders of her National League for Democracy Party (NLD). She was arrested when the military seized power.
The army has declared a year-long state of emergency and claimed, without evidence, that an earlier election was fraudulent.
On Tuesday, police began using water cannon against protesters in Nay Pyi Taw. Crowds withstood the barrage of water fired at them and refused to retreat, according to Reuters news agency.
There are also numerous unconfirmed reports of police officers crossing over to join protesters. In some areas, police also allowed demonstrators through their barricades.
“End the military dictatorship,” people chanted.
Warning shots were eventually fired into the air, before rubber bullets were fired at protesters.
Reuters quoting a doctor reported that an X-rays indicated live ammunition had been used against the woman with critical head injuries.
Military Justify Coup:
In a televised address on Monday Min Aung Hlaing insisted the seizure of power was justified due to “voter fraud”, accusing the electoral commission of failing to investigate irregularities over voter lists in November’s election.
Min Aung Hlaing promised new elections overseen by a new “reformed” election commission, and said the military would hand power to the winner.
He also said his rule would be “different” from what was effectively a 49-year military grip on power that ended in 2011. He spoke of achieving a “true and disciplined democracy”.