PHNOM PENH, Cambodia — A woman who threw a shoe at a billboard depicting Cambodian Prime Minister Hun Sen has been arrested after she was repatriated from Thailand, where the U.N. refugee agency reportedly had formally recognized her as a refugee.

Human Rights Watch called on the Cambodian government to immediately release labor activist Sam Sokha and criticized Thai authorities for sending her back against her will.

The New York-based group said her forced repatriation violated the customary principle of international law that “prohibits the return of anyone to a place where they would face the threat of persecution, torture, or other serious human rights violations.”

Kampong Speu provincial police Gen. Sam Samoun said Sam Sokha was returned to Cambodia on Thursday and was being sent to his province on Friday to begin serving a two-year prison sentence. He said she was arrested by Thai authorities after a request from the Cambodian government. Human Rights Watch said she was detained in Thailand on Jan. 5.

Sam Samoun said the provincial court convicted Sam Sokha in absentia on Jan. 25 of “insult of a public official” and “incitement to discriminate.”

A 13-second video clip that circulated on the internet last April showed Sam Sokha looking at a roadside ruling party billboard, then throwing one shoe at the image of Hun Sen and a second shoe at an image of one of his party colleagues. “This man even came here to destroy the nation,” Sam Sokha can be heard saying in the video.

“People have every right to criticize, insult, and satirize their government or political leaders without fear of retribution,” Chak Sopheap, executive director of the Cambodian Center for Human Rights, said last April. “It is unacceptable and unlawful for state authorities to subject individuals to judicial harassment and potential criminal charges simply for expressing their negative opinion of those in power.”

Hun Sen’s Cambodian People’s Party stepped up prosecutions of critics and political opponents ahead of nationwide local elections last year and a general election next year. Media outlets seen as critical of the government were forced to shut down.

Hun Sen has been in power for three decades, and while maintaining a framework of democracy, tolerates little opposition. But his grip seemed shaken in 2013’s general election, when the opposition Cambodia National Rescue Party mounted a strong challenge, winning 55 seats in the National Assembly and leaving Hun Sen’s party with 68. Cambodian courts, which are generally seen as acting under the influence of the government, dissolved the opposition party last November, depriving it of all its seats in parliament.

“Thailand was fully aware of Sam Sokha’s status as a refugee, yet still returned her to Cambodia, where she is likely to face a prison term for expressing her political views,” Brad Adams, Asia director at Human Rights Watch, said in a statement. “It’s sad but not surprising that a military junta would do a favor for a neighboring dictator, but they should not cement their friendship at the expense of a refugee.”

Thailand has been under military rule since 2014.