Thirty-eight people were killed in Myanmar yesterday as the military tried to quell protests in several towns and cities, the United Nations said, the most violent day since demonstrations against last month's military coup first broke out.
Police and soldiers opened fire with live rounds with little warning, witnesses said.
The bloodshed occurred one day after neighbouring countries had called for restraint in the aftermath of the military's overthrow of the elected government of Aung San Suu Kyi.
"It's horrific, it's a massacre. No words can describe the situation and our feelings," youth activist Thinzar Shunlei Yi told Reuters via a messaging app.
The dead included four children, an aid agency said. Hundreds of protesters were arrested, local media reported.
"Today it was the bloodiest day since the coup happened on the 1st of February. We had today — only today — 38 people died. We have now more than over 50 people died since the coup started, and many are wounded," United Nations special envoy on Myanmar, Christine Schraner Burgener, said in New York.
Schraner Burgener said that in conversations with Myanmar's deputy military chief Soe Win, she had warned him that the military was likely to face strong measures from some countries and isolation in retaliation for the coup.
"The answer was: 'We are used to sanctions, and we survived'," she told reporters in New York. "When I also warned they will go in an isolation, the answer was: 'We have to learn to walk with only few friends'."
Western countries, including the United States, Britain, Canada and the European Union, have implemented or are considering targeted sanctions to squeeze the military and its business allies.
The 15-member UN Security Council has voiced concern over the state of emergency, but stopped short of condemning the coup last month because of opposition by Russia and China, who view the developments as internal affairs of Myanmar. Any action by the council beyond a statement is unlikely, diplomats say.
A spokesman for the ruling military council did not answer telephone calls seeking comment.
Ko Bo Kyi, joint secretary of the Assistance Association for Political Prisoners rights group, had said earlier the military killed at least 18. But the toll rose by the end of the day.
In the main city Yangon, witnesses said at least eight people were killed, one early in the day and seven others when security forces opened sustained fire in a neighbourhood in the north of the city in the early evening.
"I heard so much continuous firing. I lay down on the ground, they shot a lot," protester Kaung Pyae Sone Tun, 23, told Reuters.
A protest leader in the community, Htut Paing, said the hospital there had told him seven people had been killed. Hospital administrators were not available for comment.
After nightfall, Yangon residents lit candles and held prayers for the dead.
In the central town of Monywa, six people were killed, the Monywa Gazette reported. Others were killed in the second-biggest city Mandalay, the northern town of Hpakant and the central town of Myingyan.
Save the Children said in a statement four children were among the dead, including a 14-year-old boy who Radio Free Asia reported was shot dead by a soldier on a passing convoy of military trucks. The soldiers loaded his body onto a truck and left the scene, according to the report.
The violence took place a day after foreign ministers from Southeast Asian neighbours urged restraint but failed to unite behind a call for the release of Suu Kyi and the restoration of democracy.
Pope Francis said on Twitter: "Sad news of bloody clashes and loss of life...I appeal to the authorities involved that dialogue may prevail over repression."
The European Union said the shootings of unarmed civilians and medical workers were clear breaches of international law. It also said the military was stepping up repression of the media, with a growing number of journalists arrested and charged.
"There must be accountability and a return to democracy in Myanmar," the EU said.
Security forces breaking up protests in Yangon detained about 300 protesters, the Myanmar Now news agency reported.
Video posted on social media showed lines of young men, hands on heads, filing into army trucks as police and soldiers stood guard. Reuters was unable to verify the footage.
Democracy activist Esther Ze Naw told Reuters that the sacrifices of those who died would not be in vain.
"We shall overcome this and win," she said.
The military justified the coup by saying its complaints of voter fraud in the Nov. 8 vote were ignored. Suu Kyi's party won by a landslide in the vote and earned a second term.
The election commission said the vote was fair.
Junta leader Senior General Min Aung Hlaing has pledged to hold new elections but given no time frame.
Suu Kyi, 75, has been held incommunicado since the coup but appeared at a court hearing via video conferencing this week and looked in good health, a lawyer said.