Cambodian Prime Minister Hun Sen warned opponents Monday they would face legal action or a beating with sticks if they accused his ruling party of vote theft in national polls later this year.
One of the world's longest-serving leaders, Hun Sen will mark 38 years in power this weekend and has vowed to run again when Cambodia holds elections in July.
Speaking at a ceremony in Kampong Cham province, he said political challengers would need to choose between the courts and violence if they criticised his ruling Cambodian People's Party (CPP).
"There are only two options -- one is using legal action, the other is using sticks... What do you want?" he said.
"Either you face legal action in court or I rally CPP people for a demonstration and beat you guys up."
He also instructed lawyers to monitor speeches by his rivals.
"We won't let you accuse us of being thieves all the time. The CPP cannot accept being called thieves who steal votes. We must sue whoever says that," Hun Sen added.
He later claimed he did not encourage violence.
Scores of opposition politicians, including long-time rival Sam Rainsy, have been convicted of crimes in absentia and remain in exile.
Critics and rights groups say Hun Sen has ruthlessly crushed dissent by jailing opponents and activists ahead of every election.
In the latest mass trial last month, 36 people including Rainsy were handed between five and seven years on charges of plotting against the government.
The prime minister has promised to crush Rainsy, who was sentenced to life imprisonment in October, and to squeeze his political allies.
The emerging opposition Candlelight Party took 18 percent of the vote in last year's local polls.
Its deputy leader Son Chhay -- a long-time Rainsy ally who holds Australian citizenship -- was convicted of defamation in October and ordered to pay $750,000 in compensation to the ruling party for criticising the polls.