Myanmar security forces killed an anti-coup protester in fresh violence overnight, media reported on Monday, as activists called on armed ethnic groups to back their struggle against military rule.
After the bloodiest day since last month's military coup with 114 deaths on Saturday, security forces opened fire at a funeral on Sunday, witnesses said.
Another 13 people were killed in other incidents over the weekend, according to the Assistance Association for Political Prisoners advocacy group on Sunday, taking its total toll of civilians killed since the February 1 coup to 459.
Police and a junta spokesman did not answer calls seeking comment.
The General Strike Committee of Nationalities (GSCN), one of the main protest groups, in an open letter posted on Facebook urged armed ethnic groups "to collectively protect the people, youths, women, children and elders" who opposed military rule.
Heavy fighting has erupted between the army and some of the two dozen ethnic armed groups that control swathes of the country.
About 3,000 people fled to neighbouring Thailand after military jets bombed areas controlled by the Karen National Union (KNU) militia near the border, an activist group and media said.
At least three civilians were killed on Saturday in an air attack by the military on a village controlled by the KNU, a civil society group said. The militia earlier said it had overrun an army post near the border, killing 10 people.
Fighting also erupted on Sunday between another armed group, the Kachin Independence Army, and the military in the jade-mining area of Hpakant in the north. The Kachin forces attacked a police station and the military responded with an aerial assault, Kachinwaves media reported.
There were no reports of casualties.
People in Mandalay surrounded a police station late in the evening on Sunday, accusing the security forces of arson after five houses burned down, residents said.
"While we are singing the revolution song for him, security forces just arrived and shot at us," a woman called Aye who was at the service said. "People, including us, run away as they opened fire."
UN Special Rapporteur for Myanmar Tom Andrews said the army was carrying out "mass murder" and called on the world to isolate the junta and halt its access to weapons.
Foreign criticism and sanctions imposed by some Western nations have failed so far to sway the generals, as have almost daily protests around the country since the junta took power and detained elected leader Aung San Suu Kyi.
Senior General Min Aung Hlaing, the junta leader, said during a parade to mark Armed Forces Day on Saturday that the military would protect the people and strive for democracy.
Countries including the United States, Britain, Germany and the European Union again condemned the violence.
"It's terrible, it's absolutely outrageous," U.S. President Joe Biden told reporters in Delaware. "Based on the reporting I've gotten an awful lot of people have been killed totally unnecessarily."
The EU's top diplomat, Josep Borrell, called on the generals to stand down from what he called a "senseless path" of violence against their own people.
The top military officer from the United States and nearly a dozen of his counterparts said a professional military must follow international standards for conduct "and is responsible for protecting - not harming - the people it serves".
Myanmar's military took power saying that November elections won by Suu Kyi's party were fraudulent, an assertion dismissed by the country's election commission. Suu Kyi remains in detention at an undisclosed location and many other figures in her party are also in custody.