Myanmar soldiers battled an anti-junta civilian militia with small arms and grenades in the country's second city on Tuesday, with four protesters killed and several members of the security forces injured, authorities said. 

A prominent ethnic insurgent group captured and burned down a military base in eastern Myanmar near the Thai border early Tuesday morning, an official from the group said. 

Southeast Asian leaders will hold Myanmar crisis talks Saturday with junta leader Min Aung Hlaing who has become the focus of international outrage over a military coup and crackdown that has left more than 700 dead.

The junta is planning to release more than 23,000 prisoners nationwide, an official said Saturday, even as the military continues to detain and issue arrest warrants for anti-coup dissidents.

Anti-coup protesters in Myanmar sloshed red paint in the streets on Wednesday to symbolise the blood spilled and more than 700 lives lost in a brutal military crackdown.

Myanmar's own ambassador to the United Nations has urged "strong action" against the junta, as reports emerged of scores killed in the military's latest crackdown.

A rebel group has accused Myanmar's military of deploying "excessive force", saying on Saturday that continuous air strikes have displaced more than 12,000 unarmed civilians, including children. 

The United States on Wednesday ordered the departure of non-essential diplomats from Myanmar, amid growing violence following the military coup to oust civilian leader Aung San Suu Kyi.

The death toll in the Myanmar military's crackdown on protesters has passed 500, as armed rebel groups on Tuesday threatened the junta with retaliation if the bloodshed does not stop.

US President Joe Biden has led global condemnation of an "absolutely outrageous" crackdown by Myanmar's junta that left more than 100 people -- including several children -- dead in the bloodiest day since the coup two months ago.