The arrests are the latest in a widening crackdown on media and the opposition in Cambodia ahead of elections next year. The move further strains ties between the United States and Cambodia.
Two Cambodian journalists who worked for a US-funded radio station were charged with espionage on Saturday, the latest move in a widening crackdown on critics of authoritarian Prime Minister Hun Sen.
Uon Chhin and Yeang Socheameta, former journalists of the Washington-based Radio Free Asia, were arrested on Tuesday for allegedly providing information to a foreign power. The offense carries up to 15-years in prison.
Radio Free Asia's Phnom Penh bureau closed its office in September, citing "intimidation" and threats that it was violating tax and registration regulations.
The Cambodia Daily newspaper reported the two journalists were accused of setting up broadcasting equipment in the capital and sending news reports to Radio Free Asia's Washington bureau.
Assault on media, opposition
The espionage charges come as the Hun Sen government has closed down 19 radio stations in recent months.
In September, the English-language Cambodia Daily was closed down due to alleged tax violations after Hun Sen attacked the publication for being "servants of foreigners."
Earlier this week, the country's main opposition party, Cambodia National Rescue Party (CNRP), was closed down after its leader Kem Sokha was arrested in early September for allegedly conspiring with the United States.
The widening crackdown on critical voices is viewed as a way for Hun Sen to cement his nearly 30-year rule ahead of elections next year.
Deepening row with United States
The South East Asian country's continued lurch towards authoritarianism has led to tense relations with the United States.
The US Senate earlier this week passed a resolution committing the United States to promoting democracy, human rights and the rule of law in Cambodia
"Cambodian Prime Minister Hun Sen has ruled the country with impunity for over three decades and throughout his rule, Hun Sen has resorted to any and all means to suppress the legitimate political opposition, harass civil society, intimidate the media, and deny the democratic aspirations of the Cambodian people," said Senator John McCain, a co-sponsor of the resolution.
Washington's influence in Cambodia has waned in recent years, with critics saying Chinese aid and investment have given Hun Sen a free hand to clamp down on freedoms.
cw/jlw (AFP, AP, Reuters)