Also read: 2 Myanmar protesters killed by police fire, reports say
At least two people were killed on Saturday in protests in Mandalay, the nation's second largest city, according to media reports.
“I condemn the use of deadly violence in Myanmar,” the UN chief said in a post on his official Twitter account later that day.
“The use of lethal force, intimidation & harassment against peaceful demonstrators is unacceptable. Everyone has a right to peaceful assembly. I call on all parties to respect election results and return to civilian rule.”
Protests growing steadily
Mass protests have grown steadily across Myanmar since the military takeover on 1 February, following escalating tensions surrounding elections held in November, which were won by the National League for Democracy (NLD). Top party members were arrested, including leader Aung San Suu Kyi.
Crowds gathered in Myanmar's capital, Nay Pyi Taw, on Sunday for the funeral of a young woman confirmed as the first person to be killed in the protests. Mya Thwet Thwet Khine, 19, died on Friday, after being shot in the head at a demonstration on 9 February.
Also read: Myanmar anti-coup protesters honor woman shot dead by police
Tom Andrews, the UN Special Rapporteur on the situation of human rights in Myanmar, lamented her death in a post on Twitter on Friday.
“Sadness & anger is how I reacted to news that Mya Thwe Thwe Khaing died of wounds inflicted by police in a callous & cowardly act as she protested the coup in Myanmar. I, and many others, mourn the loss of a courageous young woman & extend heartfelt condolences to her family,” he wrote.
'Madness' must end
On Saturday, two people were killed in Mandalay when security forces opened fire on striking shipyard workers. Mr. Andrews was “horrified at more loss of life”, noting that a teenage boy was one of the victims.
“From water cannons to rubber bullets to tear gas and now hardened troops firing point blank at peaceful protesters. This madness must end, now!” he said in a tweet on Saturday.
Earlier that day he posted: “The 33rd Light Infantry Division was reportedly involved in the lethal attacks in Mandalay today - the same division responsible for mass atrocity crimes against the Rohingya in 2017. A dangerous escalation by the junta in what appears to be a war against the people of Myanmar.”