Major ethnic armed organizations – whose rebel armies control vast swathes of the country – have also thrown their weight behind a growing civil disobedience movement and indicated they will not tolerate crackdowns on protesters by the military leaders who seized power in a Feb. 1 coup.
"What is happening right now is not about party politics," said Ke Jung, a youth leader from the Naga, a group of tribes on the remote Indian border. The Naga Party, the biggest political party in the region, released a statement condemning the coup.
"It is a fight for a system," Ke Jung told Reuters by phone. "We cannot compromise with the military, it will give us a black mark on our history."
Protests have taken place across the country of 53 million, from the southeastern shores of the Andaman Sea to the temple-studded central plains and the mountainous northern borders, demanding the military that overthrew and detained civilian leader Aung San Suu Kyi and her government surrender power and release the detainees.
On Thursday, thousands staged a protest aboard traditional fishing boats on Inle Lake in Shan state, while thousands of majority Christian ethnic Karen marked their National Day in the main city of Yangon and elsewhere with mass protests against the coup.
ETHNIC DIVISIONS
The diverse identity of the protesters - who have marched in pouring rain and scorching heat, wearing hoodies and flip flops, Spiderman costumes and traditional outfits - has shown rare unity in a country often riven along ethnic lines.
Myanmar has been at war within its borders for decades, with government troops battling ethnic armed groups seeking greater autonomy.
Minorities have often harbored deeply held grievances against the state dominated by the Bamar Buddhist ethnic majority they say has marginalized and oppressed them.
Many felt Suu Kyi's government, which came to power in a landslide 2015 election that ended nearly half a century of military rule, failed to live up to its top campaign pledge to bring peace to the fractious borderlands.
But the army that has seized power is accused of the gravest crimes against ethnic minorities, including mass killings and rapes during the expulsion of more than 730,000 Rohingya Muslims from Rakhine in a 2017. The army has been accused of genocide in a case brought at The Hague, which it denies.
The new military government has tried to appeal to ethnic leaders, giving key positions to prominent ethnic politicians. In his first public address, coup leader Senior General Min Aung Hlaing said the goal of the new junta was "eternal peace."
'END THE DICTATORSHIP'
Phado Man Nyein Maung, a former senior leader of the Karen National Union (KNU), one of the largest ethnic armed groups, and one of those who accepted positions with the junta, told Reuters a decade-long democratic experiment had not enshrined greater rights for the minority.
"Our political demands are not fulfilled with the democratic elections – this is the main lesson that we learned," Phado Man Nyein Maung said by phone.
But the KNU has sought to distance itself from him and on Thursday its leader, Saw Mutu Saypho, called for all ethnic groups to "work together to absolutely end the dictatorship."
Troops from the Democratic Karen Buddhist Army (DKBA), a splinter group of another Karen armed organization, drove into the center of one of the protests on Sunday after government troops fired shots into the air. Wielding rifles, the fighters rolled in on trucks to applause and shouts.
Other powerful groups, including the Ta'ang National Liberation Army (TNLA) and the Restoration Council of Shan State (RCSS), have also expressed support for the anti-coup movement.
TNLA leaders posted pictures on Facebook of themselves making the three-finger "Hunger Games" salute that has become a symbol of the movement. "May the military dictatorship fall down," the post said.
A spokesman for the Arakan Army (AA), which has been locked in a deadly conflict with government troops in western Rakhine state since 2018, said it was "closely monitoring the current developments inside Myanmar."
The Kachin Independence Army (KIA) in the north has not formally commented, but one senior KIA leader warned the army in a Facebook post not to shoot demonstrators.
Saw Kapi, a Karen leader and founding director of the Salween Institute think-tank, said many saw it as their "duty" to oppose the coup.
"Thousands of ethnic youths joined the nationwide protests today," he said. "Their common goal is to reject military dictatorship and establish a federal democracy in Myanmar."