Mu Sochua, a prominent deputy of Cambodia’s opposition leader, has left the country, a day after Prime Minister Hun Sen threatened further arrests of opposition politicians. Kem Sokha, leader of the opposition Cambodia National Rescue Party (CNRP), was arrested on Sept. 3 and charged with treason in a widening crackdown on critics of Hun Sen, which his opponents say is a ploy to win  general elections next year. If found guilty, Sokha could face 15 to 30 years in prison. Western countries have raised concerns about the arrest, with the European Union calling it “a dangerous political escalation”.