The country has been in turmoil since February 1, when the military ousted civilian leader Aung San Suu Kyi in a lightning coup.

Using violence and lethal force to quell a nationwide uprising, security forces have killed at least 739 people in near-daily crackdowns, according to a local monitoring group.

Coup leader Min Aung Hlaing is set to take part Saturday in a summit of regional leaders -- as part of the 10-country Association of Southeast Asian Nations (ASEAN) -- to address Myanmar's mounting crisis.

The meeting of ASEAN leaders and foreign ministers has drawn widespread criticism from activists, human rights groups and protesters for including the military regime.

In commercial hub Yangon -- where the anti-coup movement had laid low in recent weeks due to fear of crackdowns -- protesters returned to the streets, flashing three-finger salutes of resistance.

"Mother Suu and leaders -- release them immediately!" they shouted as they marched quickly past the Sule Pagoda in downtown Yangon. "What do we want? Democracy!"

The protesters came from different Yangon townships, some carrying signs that read "ASEAN please stand with Myanmar people" and "ASEAN do you need more blood... to make the right decision?"

Also angered by the bloc's invitation to Min Aung Hlaing was the so-called National Unity Government -- a group of ousted Myanmar lawmakers attempting to run a shadow administration.

On Thursday, they called on Interpol to arrest the senior general -- the same day Myanmar state media announced the lawmakers in hiding were wanted for high treason.

Amnesty International's Emerlynne Gil called ASEAN's handling of Myanmar the "biggest test in its history".

"The Indonesian authorities and other ASEAN member states cannot ignore the fact Min Aung Hlaing is suspected of the most serious crimes of concern to the international community as a whole," she said.

The junta has justified the putsch by alleging electoral fraud in November's elections -- which Suu Kyi's party had won in a landslide.

The US, EU and Britain have already imposed sanctions on top military brass, as well as on some army-linked businesses.

Before the coup, Min Aung Hlaing was already facing international sanctions over his army's role in the Rohingya crisis.

About 750,000 of the Muslim minority group fled Myanmar in 2017 following a brutal military crackdown.