The military carried out torture, murder, and other crimes against civilians following the February 1 coup, the human rights group Fortify Rights and Yale Law School's Schell Center said in a report.
Myanmar's junta chief had reportedly created a special command a day after last year's coup that carried out the deployment and operations of troops in urban areas, and authorised lethal attacks on unarmed civilians.
The junta leadership deployed snipers to kill protesters to instil fear, the human rights group Fortify Rights and Yale Law School's Schell Center said in a 193-page report released on Thursday after a joint investigation.
The report, called "Nowhere is Safe", also stated that soldiers were instructed to commit crimes and given a "fieldcraft" manual that contained no guidance on rules of war.
The investigators analysed leaked documents and 128 testimonies from various sources including survivors, medical workers, witnesses and former military and police personnel.
They said they had obtained and verified internal memos to police ordering them to arbitrarily arrest protesters, activists and members of the ousted ruling party, and cited testimony from victims of torture and other abuses.
"All individuals responsible for these crimes should be sanctioned and prosecuted," said Matthew Smith, head of Fortify Rights and co-author of the report.
A spokesman for Myanmar's military did not immediately respond to calls seeking comment on the report's findings.
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Crimes against humanity?
The report also identified 61 military and police commanders who the researchers said should be investigated for crimes against humanity, helped by information from security sources about the chain of command.
Among those were six active-duty army personnel, including a colonel and two majors.
The researchers said they established locations of more than 1,000 military units at the time of the crackdown, which they said could help prosecutors geo-locate perpetrators of crimes.
Junta chief Min Aung Hlaing's new "special command" in the capital Naypyitaw was run by four of his top generals, it said, with no others authorised to take decisions on operations by troops deployed in towns and cities.
Fortify Rights has urged members of the United Nations push for a global arms embargo on Myanmar and international legal action against its generals.
The investigation will add to global pressure on the military to halt its crackdown on opponents and the use of air strikes and shelling in civilian areas.
The junta has yet to respond but has previously dismissed accusations of atrocities as foreign interference based on falsehoods.
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