At least 80 people were killed when security forces opened fire on pro-democracy protesters in several parts of Myanmar on Saturday, the Myanmar Now news portal said.
It said the dead included 10 in the country's second-biggest city, Mandalay, 9 in the nearby region of Sagaing and 16 in the commercial capital Yangon.
The Associated Press cited a separate count issued by an independent researcher in Yangon that put the day's death toll at 74, as once again thousands of people staged rallies all over the country.
The embassies of the European Union and the United Kingdom in Myanmar condemned the latest killings of "unarmed civilians, including children," describing them as "indefensible acts."
The US embassy said the killings were "not the actions of a professional military or police force."
One activist in Mandalay told DW that soldiers were entering neighborhoods dressed as civilians "with concealed guns and weapons."
"They are not just cracking down on the protesters," David, whose name has been changed, said. "They are now entering the neighborhood and shooting and beating and looting everything that's in their sight."
"Every corner of the streets are being burned down," he warned.
Armed Forces Day turns deadly
The fresh crackdown came as Myanmar's military, the Tatmadaw, held the annual "Armed Forces Day" parade, using the occasion to condemn the opposition and promise elections.
"The army seeks to join hands with the entire nation to safeguard democracy," General Min Aung Hlaing said in a speech broadcast on state television after the parade in the capital, Naypyitaw.
The parade was a show of force for the Tatmadaw, with military vehicles, firepower and soldiers marching in formation.
Russian Deputy Defense Minister Alexander Fomin also attended the parade. On Friday, he met with senior Tatmadaw leaders and offered his support.
"Russia in a true friend," Min Aung Hlaing said Friday.
There were no signs of officials from other countries, although international guests are usually present at the parade.
New elections promised
Myanmar's military took over the country's democratically elected government in a coup on February 1, unleashing a massive protest movement against its rule.
Aung San Suu Kyi and other leaders from National League for Democracy (NLD) have been detained since the coup.
However, the Tatmadaw claims that the army had to seize power because of "unlawful acts" and corruption.
On Saturday, Min Aung Hlaing reiterated a promise to hold elections, without specifying a date.
General warns protesters of 'head shots'
Min Aung Hlaing claimed that authorities wanted to protect people and restore peace, while warning against further protests.
"Violent acts that affect stability and security in order to make demands are inappropriate," he said in an earlier televised speech on Friday evening.
"You should learn from the tragedy of earlier ugly deaths that you can be in danger of getting shot in the head and back."
The death toll from the military crackdown reached nearly 400 on Saturday.
The violent response from the military leaders has drawn international condemnation and sanctions.
According to the Assistance Association for Political Prisoners (AAPP) activist group, which has been tracking killings of demonstrators in Myanmar, at least 25% of protester deaths have come from shots to the head.
This has raised suspicions that protesters have been deliberately targeted by security forces for killing.