A shadow government in Myanmar seeking to reverse the February 1 coup has joined forces with a rebel group to "demolish" junta rule, it said Saturday.

Myanmar has been in turmoil since the military overthrew Aung San Suu Kyi and her National League for Democracy government and launched a brutal crackdown on dissent.

A group of ousted lawmakers later set up a shadow "National Unity Government" which has sought to bring anti-coup dissidents together with Myanmar's myriad ethnic rebel fighters to form a federal army to challenge the junta.

On Saturday, the rebel Chin National Front signed an agreement to "demolish the dictatorship and to implement a federal democratic system" in Myanmar, the NUG said in a statement.

They pledged "mutual recognition" and to "partner equally" the statement added, without giving further details. A CNF spokesperson could not immediately be reached for comment.

The group -- which represents the mainly Christian Chin minority in western Myanmar -- signed a ceasefire with the country's military, also known as Tatmadaw, in 2015.

In recent years its fighters have dwindled.

"The CNF has no real military strength, so this move is symbolic," Richard Horsey, senior advisor on Myanmar to the International Crisis Group, told AFP.

"But [it is] nevertheless significant as CNF has been quite prominent in the peace process, due to its well respected political leaders in exile."

Myanmar's "National Unity Government" has sought to bring anti-coup dissidents together with myriad ethnic rebel fighters to form a federal army to challenge the junta
Myanmar's "National Unity Government" has sought to bring anti-coup dissidents together with myriad ethnic rebel fighters to form a federal army to challenge the junta AFP / STR

Several of Myanmar's rebel armed groups have condemned the military coup and the use of violence against unarmed civilians.

Some are also providing shelter and even training to dissidents who flee into their territories.

But the more than 20 outfits have long distrusted the ethnic Bamar majority -- including lawmakers affiliated with Suu Kyi's government.

On Friday, the NUG released a video it said showed the first batch of fighters from its "People's Defence Force", formed to protect civilians, completing their training.

Around a hundred recruits were shown marching across flat ground surrounded by jungle. None appeared to be carrying weapons.

"Let all Burmese people be freed from military slavery," the recruits were heard shouting together.

More than 800 people have been killed by the military, according to a local monitoring group, though the coup leader has given a much lower civilian toll.

The junta has classified the NUG and the People's Defence Force as "terrorists", meaning anyone speaking to them -- including journalists -- can be subjected to charges under counter-terrorism laws.

Coup leader Min Aung Hlaing has justified his February 1 power grab by claiming electoral fraud in November elections won by Suu Kyi's NLD party.