At least eight people have been injured in Cambodia's capital as police fired smoke grenades and used electric batons to break up an anti-government demonstration.
Several hundred people, led by radio station owner Mam Sonando, gathered in front of the Ministry of Information on Monday to press demand for the government critic to be allowed a license for a television channel.
The government last week rejected the application, saying there was no frequency available. All existing stations are closely linked to Prime Minister Hun Sen and Cambodia has been accused of only granting television licences to pro-government media.
Protesters and journalists were hit by police batons during Monday's rally, according to rights activists.
Activist Am Sam Ath of local rights group Licadho condemned the crackdown on the protesters as a "serious violation of human rights".
Phnom Penh City Hall spokesman Long Dimanche said police dispersed the protest because it had not been permitted and could have led to violence.
The government imposed an indefinite ban on street demonstrations in Phnom Penh after a wave of protests in early January challenging the results of last year's election, which the opposition alleges was rigged.
It was illegal demonstration. So the authorities just implemented the law
"It was illegal demonstration. So the authorities just implemented the law," Long Dimanche said.
Sonando, who has dual Cambodian-French citizenship, was convicted in October 2012 on charges including insurrection and inciting people to take up arms against the state.
He was released from jail last March after a court cleared him of a secessionist plot, slashing his 20-year jail term and ordering his release from prison.
Baton-wielding police clashed on Sunday with protesters - including Buddhist monks - demanding higher wages for garment workers and the release of 23 people arrested during a recent bloody crackdown on striking garment workers, which left at least four civilians dead.
Authorities have quelled recent street protests against Hun Sen. He faces mounting criticism by rights groups of his government's suppression of street protests intended to challenge his nearly three-decade rule.
Human Rights Watch has condemned the recent actions by the Cambodian government and is urging the United Nations member countries to press the country's leadership to abide by previous commitments and fulfil new rights pledges.
Cambodia is scheduled to appear before the UN Human Rights Council's Universal Periodic Review (UPR) in Geneva on Tuesday.
"Hun Sen's government violates human rights on a daily basis by violently preventing the opposition, trade unions, activists and others from gathering to demand political change," said Juliette de Rivero, Geneva director at Human Rights Watch.