The country has been in uproar since the military ousted civilian leader Aung San Suu Kyi in a February 1 coup, triggering a massive uprising which authorities have sought to quell with lethal force.

Some in the anti-junta movement have set up local militias armed with home-made weapons to protect their towns from security forces -- which have killed at least 790 civilians according to a local monitoring group.

In the western state of Chin, the town of Mindat has emerged as a hotspot for unrest, where some residents have formed the Chinland Defence Force (CDF).

"We have at least five members killed and over 10 were wounded" this week, said a CDF spokesman, adding that five Mindat residents were also arrested by the military.

With mobile data blocked across the country, details about the fighting have been slow to come out, and on-the-ground verification is made harder as locals are fearful of retaliation.

The spokesman, who declined to be named, told AFP that CDF fighters set fire to several army trucks, destroying them, and ambushed reinforcement troops, while the military has attacked the town with artillery.

By Sunday, the CDF had retreated into the jungle, he said.

"We will not stay any more in the town... but we will come back to attack soon," he said. "We only have home-made guns. This was not enough."

He added that residents remaining in Mindat -- which has been under martial law since Thursday -- were afraid to leave their homes for fear of being targeted by the military.

The US and UK embassies in Myanmar sounded the alarm Saturday on Mindat's unrest, calling for security forces to cease violence.

"The military's use of weapons of war against civilians, including this week in Mindat, is a further demonstration of the depths the regime will sink to to hold onto power," the US embassy said in a tweet Saturday.

The British embassy said the Mindat violence "cannot be justified".

"Evidence of atrocities should be sent to the (United Nations Independent Investigative Mechanism for Myanmar) so perpetrators can be held to account," the embassy tweeted, referring to a committee that collects evidence of international crimes.

State-run newspaper New Light of Myanmar reported Sunday that a military tribunal would be convened to try "perpetrators of terrorist attacks" in Mindat.

Across the country, anti-coup protesters continue to march for democracy -- with demonstrators in northern Hpakhant holding signs that said "Stay strong, Mindat".