(CNN) Two top UN officials condemned Myanmar's military junta in the wake of the bloodiest day of protests yet against the military coup that overthrew the country's elected government, as defiant protesters turned out once more Sunday.
At least 114 people were killed Saturday during demonstrations in 44 towns and cities across the country, according to a tally by the independent Myanmar Now news outlet. CNN has been unable independently to confirm the number of people killed.
In a joint statement, Alice Wairimu Nderitu, UN Special Adviser on the Prevention of Genocide, and Michelle Bachelet, UN High Commissioner for Human Rights, urged the Myanmar military to "immediately stop killing the very people it has the duty to serve and protect."
The officials also "strongly condemned the Myanmar military's widespread, lethal, increasingly systematic attacks against peaceful protesters, as well as other serious violations of human rights since it seized power on 1 February 2021."
The UN Special Rapporteur for Myanmar said the army was carrying out "mass murder" and called on the world to isolate the junta and halt its access to weapons.
According to the latest tally by the nonprofit Assistance Association for Political Prisoners, at least 423 people have been killed in Myanmar since the military coup on February 1.
At least six children between the ages of 10 and 16 were among those killed on Saturday, Myanmar's Armed Forces Day, according to news reports and witnesses, Reuters reported.
Despite the bloodshed, some protesters returned to the streets Sunday to demonstrate against Myanmar's military in parts of Yangon and other districts across Myanmar.
Live streams Sunday showed people marching to protest the military in Phayar Then Zu along the Thailand-Myanmar border, filling the streets. Some protesters also took to the streets in Magway and Myingyan, according to Myanmar Now.
Residents told local media that military forces had been firing indiscriminately in Yangon since early morning. Images shared on social media purport to show at least one man was shot dead in Hlaing Township on Sunday.
Local media also reported a woman was shot in the head by security forces in Mon Ywa, central Myanmar.
A 40-year-old Mandalay resident was shot and burnt alive by military troops, according to Myanmar Now, which quoted residents and a night guard in the victim's neighborhood. Its report added that locals were unable to help the victim due to "continuous gunfire from the troops."
Also in Myingyan, Mandalay, a 24-year-old woman was killed and two others were injured when the coup regime's gunmen opened fire on protesters on Sunday, according to Myanmar Now.
The independent news outlet also reported the killing of a 20-year-old nurse on Sunday in Monywa. Its report said the nurse was shot in the head by the military as she attended to others injured by military troops. She was reportedly a part of a rescue team. A man who is yet to be identified was also shot dead by the military alongside the nurse, Myanmar Now added.
In another incident, it reported that a women's rights activist, part of the "Women for Justice" organization in Myanmar was killed by the military during a crackdown on an anti-coup protest in Kalay, Sagaing.
Reuters news agency reported, quoting witnesses, that Myanmar security forces opened fire Sunday at people gathered in the town of Bago for the funeral of one of the 114 people killed the previous day. There were no immediate reports of casualties in the gunfire.
CNN cannot independently verify the reports.
CNN has also repeatedly requested comment from Myanmar's military but has not received a response.
The bloodshed Saturday drew renewed Western condemnation, with countries including the United States, Britain and the European Union speaking out.
But foreign criticism and the sanctions imposed by some Western nations have failed so far to sway the military leaders, as have almost daily protests around the country since the junta took power and detained elected leader Aung San Suu Kyi.
"We salute our heroes who sacrificed lives during this revolution and We Must Win This REVOLUTION," one of the main protest groups, the General Strike Committee of Nationalities (GSCN), posted on Facebook, according to Reuters.
UN Special Rapporteur Tom Andrews said it was time for the world to take action -- if not through the UN Security Council then through an international emergency summit. He said the junta should be cut off from funding, such as oil and gas revenues, and from access to weapons.
"Words of condemnation or concern are frankly ringing hollow to the people of Myanmar while the military junta commits mass murder against them," he said in a statement.
Nderitu and Bachelet called the killings "shameful, cowardly, brutal actions of the military and police, who have been filmed shooting at protesters as they flee, and who have not even spared young children."
"This situation has also put at further risk the already vulnerable ethnic and religious minorities in Myanmar, including the Rohingya," their joint statement said.
They called on the international community to act, adding: "The international community has a responsibility to protect the people of Myanmar from atrocity crimes."
The top military officer from the United States and nearly a dozen of his counterparts said in a statement that a professional military must follow international standards for conduct "and is responsible for protecting -- not harming -- the people it serves."
The 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.
Heavy fighting has also erupted between the army and the ethnic armed groups that control swathes of the country, according to Reuters.
Military jets killed at least two members of the Karen National Union (KNU) militia in a bombing raid near Thailand and many civilians fled across the border, said David Eubank, founder of the Free Burma Rangers, a relief organization.
In an air attack by the military on Saturday, at least three civilians were killed in 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, Reuters reported.
About 3,000 villagers fled across Karen state's border into Thailand on Sunday, Reuters reported, citing an activist group, the Karen Women's Organization, and media outlet Thai PBS.
Fighting 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.
A junta spokesman did not answer calls from Reuters seeking comment on the killings or the fighting.
Senior Gen. Min Aung Hlaing, the junta leader, said during a parade to mark Armed Forces Day that the military would protect the people and strive for democracy.