ONE of Myanmar's main ethnic minority rebel groups has warned of a growing threat of major conflict and called for international intervention against a military crackdown on opponents of last month's coup. Myanmar has been in turmoil since the army ousted an elected government led by Nobel laureate Aung San Suu Kyi on February 1, detaining her and reimposing military rule after a decade of tentative steps towards democracy. While cities and towns across the country have been consumed by protests against the military, fighting has also flared between the army and insurgents in frontier regions and refugees are spilling…