Former Cambodian opposition leader Sam Rainsy has filed a legal case in the United States to get Facebook to release information on Prime Minister Hun Sen's use of the social media platform, his legal team said.
Lawyers for Sam Rainsy, who fled Cambodia in 2015 to escape a conviction for defamation he says was politically motivated, said he sought the information to help him in his own legal cases in Cambodia.
Supporters of Hun Sen have built a strong presence on Facebook.
Sam Rainsy wants information on allegations of "false likes" on Hun Sen's Facebook account, accusations that the platform had been used to make death threats and the use of state money for advertisements, his legal team said in a statement on Wednesday.
Government spokesman Phay Siphan said the lawsuit was "not useful".
The case highlights the growing global nature of the challenge to Facebook Inc over its role in political debate after accusations that social media was used for meddling in votes in Britain, the United States and elsewhere.
Facebook has become an ever more important platform for political news in Cambodia as some media outlets critical of Hun Sen have been forced to shut.
Hun Sen, 65, has been criticized by Western countries over a ban on the main opposition party and the arrest of its leader less than a year away from a general election on July 29.
Paris-based Sam Rainsy sought "critical information in Facebook's possession regarding Hun Sen's misuse of social media to deceive Cambodia's electorate and to commit human rights abuses," according to the statement.
"The petition raises fundamental questions about how Facebook should deal with human rights abusers who manipulate elections," said Sam Rainsy's attorney, Richard J. Rogers, of rights group Global Diligence LLP.
Facebook did not immediately respond to a request for comment on the case, which Sam Rainsy's lawyers said had been brought in the U.S. District Court for the Northern District of California.
Hun Sen's Facebook profile was private, the Cambodian government spokesman added.
"The Facebook profile of the Samdech Prime Minister is private, it's not a terrorist group to cause any insecurity with any country," said Phay Siphan, using the official title for Hun Sen, who has ruled Cambodia for more than 33 years.
Facebook, which has more than 2 billion users globally, tells advertisers they have the potential to reach 6.6 million people in Cambodia, from a population of nearly 16 million.
It says more than 5.5 million people have expressed an interest in, or liked, pages related to Hun Sen, of whom 1.8 million are in Cambodia.
Comparable figures for Sam Rainsy are 2.2 million people expressing an interest, with 1.7 million within Cambodia.
(Reporting by Prak Chan Thul and Matthew Tostevin; Editing by Amy Sawitta Lefevre and Clarence Fernandez)