Myanmar's military cracked down on anti-coup protesters on Saturday, killing at least one according to a witness, as the junta leader sat down with heads of states in a regional summit over the violence.

The country has been in turmoil since the military ousted civilian leader Aung San Suu Kyi in a coup, triggering a mass uprising from all corners of Myanmar society demanding a return to democracy.

Cities, rural areas, remote mountainous regions and even the rebel-ruled territories along Myanmar's borders have erupted in dissent, protesting near-daily for the military to step down.

While Western powers have imposed targeted sanctions on military top brass, regional leaders from the 10-country Association of Southeast Asian Nations have sought to open a communications channel with the junta.

Senior General Min Aung Hlaing took part in a high-level summit Saturday in Jakarta to discuss Myanmar's mounting crisis -- his first overseas trip since he seized power.

But across Myanmar Saturday, protesters persisted in taking to the streets -- angered by ASEAN's invitation to the junta regime.

A demonstration on motorbikes where protesters flashed the three-finger salute of resistance as they drove outside Myanmar's capital Naypyidaw turned violent by afternoon when police and soldiers opened fire.

A 50-year-old protester was detained and killed, a witness told AFP.

"Police held him on each side, then a soldier shot him in the back," the 27-year-old protester said, adding that security forces took the man's body.

Protests continued in Myanmar on Saturday
Protests continued in Myanmar on Saturday ANONYMOUS / Handout

"We only had the three-finger salute, but they had weapons to take our lives," he said.

"I want to deliver a message to the ASEAN leaders... do not support him (Min Aung Hlaing)."

Saturday's violence adds to the more than 740 people killed since the coup, according to a local monitoring group.

Clashes between the military and ethnic rebel groups with territory along Myanmar's eastern and western borders have also ramped up in recent weeks.

Among the most vocal opponents of the coup is the Karen National Union (KNU), who are sheltering dissidents and activists in their territory along the Thai-Myanmar border.

On Friday night, two people in the southern city of Thaton were killed in crossfire between the military and the KNU, a resident told AFP.

"No one dared to retrieve the two dead bodies last night, and the people went to take them this morning," said the resident, who blamed the military for the shooting.

The KNU's head of foreign affairs Padoh Saw Taw Nee said the fighting had killed at least one civilian.

He added that another "small clash" occurred Saturday morning along the Salween river, which serves as a border between Thailand and Myanmar.

In March the military launched airstrikes into the KNU's territory, displacing thousands of civilians from their homes -- some of whom crossed into Thailand briefly for refuge.