PHNOM PENH: A Cambodian court on Tuesday charged opposition leader Kem Sokha with treason and espionage over an alleged conspiracy with unnamed foreigners, as strongman premier Hun Sen intensifies his assault on his political enemies. Opponents of Hun Sen, as well as NGOs and the critical press, have increasingly been smothered by court cases and threats before a crucial general election next year. Kem Sokha, 64, a veteran opposition politician who has formally led the Cambodia National Rescue Party (CNRP) since March, is accused of conniving in a “secret plan” with foreign entities which began in 1993, according to a court statement. It said evidence of a conspiracy was substantial enough to charge him under the penal code section for “treason and espionage, “ which carries up to 30 years in jail. Kem Sokha was arrested early Sunday in a swoop by hundreds of security force members at his home in the Cambodian capital.