"From a fenced-off compound close to the Myanmar border in northern Thailand, a rebel leader offers a bleak view of Myanmar's future, as the country is cleaved apart by a military coup. The possibility of a deepening civil war in Myanmar is "high," Gen. Yawd Serk said from his administrative base in Chiang Mai province. "The world has changed. I see people in the cities won't give up. And I see (coup leader) Min Aung Hlaing won't give up. I think there is possibility that civil war might happen." Yawd Serk is an old hand at confronting military rulers. He is chairman of the ethnic minority political organization Restoration Council of Shan State (RCSS) and founder of its armed wing, the Shan State Army (SSA), which controls large pockets of land in Myanmar's east. His is one of more than two dozen ethnic armed groups that have been fighting against the Myanmar military -- know as the Tatmadaw -- and each other in the country's borderlands for greater rights and autonomy, on and off for 70 years. Since the military seized power on February 1, deposing the elected government of Aung San Suu Kyi, many of these rebel groups -- including the RCSS -- have expressed support for non-violent nationwide protests against junta rule, and condemned the indiscriminate brutality and deadly use of force inflicted on Burmese civilians by junta-controlled soldiers and police. But as security forces continue their deadly campaign, there are signs the country is reaching a turning point where rebel groups could engage in renewed conflict, while some in the protest movement start to push for armed resistance in a bid to defend themselves. A senior rebel leader and several protesters, whom CNN is not identifying for security reasons, say a small, but growing number of pro-democracy activists are heading into the jungles where they are receiving combat training from ethnic militias. There are also increasing calls from the urban centers for the ethnic rebel groups to do more to protect people from the military violence. A protest group formed by some of the myriad ethnic minorities in the country recently called on 16 ethnic armed organizations to "urgently" protect the lives of the people. And last Tuesday, three rebel groups in the north of the country, which call themselves the Three Brotherhood Alliance, said if the Myanmar military does not stop killing civilians, "we will join the spring revolution with all the ethnicities for self defense actions." If the military "continues to shoot and kill people, it means the junta have simply transformed themselves into terrorists," Yawd Serk said. "We won't just sit still, we will find every means to protect the people..."