An ethnic minority armed group in Myanmar has seized control from the country’s ruling junta of a lucrative border crossing to China, local media and a security source said Sunday. Clashes have raged across Myanmar’s northern Shan state, close to the Chinese border, after an armed alliance of three ethnic minority groups launched an offensive against the military in October. The groups have seized dozens of military positions and a town important for trade with China, choking commerce routes for the cash-strapped junta.