PHNOM PENH (AFP) - An outspoken Cambodian opposition lawmaker faces up to five years in prison after he was charged on Tuesday (April 4) with inciting revolt by criticising government border maps, as premier Hun Sen threatened to "handcuff" anyone who raises the issue.
Um Sam An, a dual Cambodian-US national, was arrested late Sunday in Siem Reap province after returning from overseas.
He was a prominent campaigner against Hun Sen's government for using contested maps as a guideline to demarcate the border with Vietnam, accusing it of conceding land to the neighbouring country.
Prosecutors at a Phnom Penh court ordered his detention pending trial.
Interior Ministry spokesman Khieu Sopheak told AFP the lawmaker used the border issue to incite people to revolt against the government.
"He also incited racism between Cambodia and Vietnam. We cannot accept this," he added.
Under Cambodia's criminal code he faces up to five years in jail if convicted.
Strongman Hun Sen on Tuesday warned of further arrests.
"Anybody who dares to say the government is using fake maps must be handcuffed," Hun Sen said in a speech broadcast on a state-run radio.
Hun Sen also asked parliament, which is dominated by lawmakers from his ruling party, to vote to allow the court to continue proceedings against Um Sam An - who as a lawmaker is meant to be exempt from prosecution.
Parliament will discuss the case later Tuesday.
Anti-Vietnamese sentiment is strong in parts of Cambodia and is often used by the opposition as a touchstone issue.
Sam Sokong, a lawyer for Um Sam An, confirmed the charges with AFP through a text message.
"His expression did not damage society," he added.
Cambodia's opposition party has long been critical of Phnom Penh's cosy ties with Hanoi and routinely accuses Vietnam of taking Cambodian territory along the 1,270km border, which is not fully demarcated.
The Cambodia National Rescue Party (CNRP) denounced the arrest of Um Sam An as a "serious violation of the principle of parliamentary immunity".
An opposition senator was also arrested last year after Hun Sen accused him of committing treason by posting a "doctored" version of an old treaty about the Vietnamese border on Facebook.
He is still in detention as his trial has been delayed.
Hun Sen, who has ruled Cambodia for more than three decades, is highly sensitive to criticism that he is too soft on Vietnam over the disputed areas of the shared border.