The United Nations' human rights chief warned on Tuesday that Myanmar could be headed for a "full-blown" conflict similar to the decade-long war in Syria.
"I fear the situation in Myanmar is heading for a full-blown conflict. States must not allow the deadly mistakes of the past in Syria and elsewhere to be repeated," Michelle Bachelet said in a statement.
"The military seems intent on intensifying its pitiless policy of violence against the people of Myanmar, using military-grade and indiscriminate weaponry," she added.
She called on the international community to step up efforts to put an end to the repression in the southeast Asian country.
The junta seized power in a February 1 coup, arresting hundreds of opposition lawmakers including the country's elected leader, Aung San Suu Kyi, and cracking down violently on subsequent pro-democracy protests.
According to the Assistance Association for Political Prisoners (AAPP), which has been counting casualties and arrests since the coup, 714 people have now lost their lives with more than 3,050 in detention.
Reports have also flagged that security forces are charging relatives of people killed a "fine" of roughly $90 (€75) to claim their bodies.
The military argues there was widespread fraud during the November legislative elections, which Suu Kyi's party won by a landslide, and has likened the protest movement to terrorism.
Bachelet said the repression "clearly echoes" the situation in Syria in 2011 because "there too, we saw peaceful protests met with unnecessary and clearly disproportionate force."
"The State's brutal, persistent repression of its own people led some individuals taking up arms, followed by a downward and rapidly expanding spiral of violence all across the country," she continued.
Clashes between the military and ethnic armed groups have intensified in recent days in the states of Kachin, Shan and Kayin with the junta also employing airstrikes, Bachelet said.
The ongoing repression and escalation of violence have led to thousands of people being internally displaced while hundreds have sought refuge in neighbouring countries.
The European Union, UK and US have all slapped sanctions on several high-ranking military officials as well as on state-backed conglomerates in response to the coup and ongoing violence.
But Bachelet stressed that "statements of condemnation, and limited targeted sanctions, are clearly not enough."
"States with influence need to urgently apply concerted pressure on the military in Myanmar to halt the commission of grave human rights violations and possible crimes against humanity," she said.
She highlighted the need to cut off the supply of arms and finances to the military leadership and appealed to neighbouring countries to open their borders to refugees from Myanmar.