A Cambodian government e-mail leaked to VOA indicates the government has been pressuring Internet service providers to block websites containing anti-government material.
The e-mail, provided Thursday to the VOA Khmer service by an ISP employee, comes from the account of a senior official in the Ministry of Post and Telecommunications.
It expresses "appreciation" to several service providers for their cooperation with the ministry and admonishes three others, urging them to "kindly take immediate action."
Cambodia's ruling party controls much of the nation's broadcast and print media, but has until now left the Internet unfettered.
However, Internet users and bloggers say access to certain sites that criticize the Cambodian government has been blocked or redirected since the rise of Internet-driven protests across the Middle East in recent weeks.
The leaked e-mail suggests the anti-government website KI Media has been a particular target of the government, which publicly denies any effort to block websites.