Phnom Penh, Cambodia - An outspoken opposition member and proponent of sanctions against Cambodia was arrested and charged with "incitement", just days after Prime Minister Hun Sen threatened to renew his political crackdown if the European Union (EU) went ahead with plans to withdraw trade benefits.

Kong Mas, a member of the dissolved Cambodia National Rescue Party (CNRP), was charged on Saturday in the capital, days after his arrest, his lawyer said.

"Phnom Penh court prosecutor decided to charge officially Mr Kong Mas of incitement and insulting," Sam Sokong said.

Incitement, a catch-all charge often used to imprison regime critics, carries a prison sentence of six months to two years.

The EU has begun the process of withdrawing its Everything But Arms (EBA) deal with Cambodia, a favourable trade agreement that allows the Southeast Asian country to export goods to Europe with reduced tariff rates.

A prerequisite for the deal is respect for various human rights obligations. The EBA has been on the chopping block since the main opposition party - the CNRP - was dissolved and its president arrested for treason ahead of the 2018 national election.

Just before his arrest on Wednesday, Kong Mas posted a Facebook status welcoming new, unrelated tariffs on Cambodia's rice exports, calling it the "first round".

In a previous interview with Al Jazeera, Kong Mas said he supported sanctions and hoped it would lead to mass protests that would force the government to solve the political situation.

Threat over sanctions

The lead up to elections in July 2018 was characterised by months of threats and arrests, but after Hun Sen successfully retained power, the situation relaxed with many political prisoners released or pardoned.

But on Wednesday, former CNRP provincial committee leader Mas was arrested in Phnom Penh.

"Please don't forget that if you sanction me, it equally means that [you] beat the opposition in Cambodia to death," Hun Sen warned the EU during a speech marking the 34th anniversary of his rule.

In his speech, the prime minister warned critics to be prepared to flee if the EBA is revoked, declaring: "I won't forgive them."

CNRP founder Sam Rainsy said Hun Sen's threats show he has "lost his mind".

"If he wants to avoid those sanctions because he cares about the well-being of the Cambodian people, he just has to reverse his repressive policies and start negotiations with the European Union in order to restore democracy in Cambodia," he told Al Jazeera via email.

Shortly after Mas's arrest, the government released a sharp statement warning the public not to use "inappropriate words and negative visions, making confusion to the public" when discussing the EBA.

Initially, Hun Sen had laughed off threats of sanctions, daring the United States and the EU to take action while claiming China will fill any gaps left behind.

Now he seems to be toeing a different line, telling the EU that he's open to negotiations but only if the EBA remains in effect.

EBA agreement

Cambodia exports things worth over five billion euros ($5.6bn) to the EU under the EBA agreement, the bulk of which is contributed by the country's enormous garment sector. The industry is 800,000 strong and historically prone to protests, something Hun Sen has been eager to avoid.

Ear Sophal, a Cambodian-American associate professor of world affairs and diplomacy at Occidental College, said withdrawing the EBA would be "catastrophic".

The minister of commerce had previously warned Hun Sen that losing the EBA would cost Cambodia's economy $676m.

"Who is going to pay for this? The workers will, through mass layoffs and shrinkage in the sector," Sophal said.

Mann Senghak, vice president of the FTUWKC trade union, said Hun Sen fears the garment sector's influence.

"He understands that the garment sector has a lot of people that are easy to organise," he said.

Senghak personally does not support sanctions.

"For me, the EBA might impact a lot to the life and income of workers and their families. They may lose their jobs, I'm worried about their futures," he said. "If those countries withdraw, I would feel pity."

Union leaders in Cambodia don't exactly speak freely, however, and openly supporting sanctions can be a dangerous position to hold. Chea Mony, brother of assassinated union leader Chea Vichea, fled the country after receiving multiple legal complaints from pro-government unions over his advocacy of sanctions.

George Edgar, the EU ambassador to Cambodia, declined to comment on Kong Mas's arrest, citing a lack of information. His comment on the EBA seemed to suggest that the way forward for Hun Sen was to relax political pressure, not ramp it back up.

"[If] Cambodia were to take measures to swiftly remedy the situation that has led to the initiation of the withdrawal procedure, the EU would reconsider the situation," he said via email.

Sophal said the government may be trying to send a message to the EU with Kong Mas's arrest, but it's "the wrong message". Accusing Hun Sen of holding the Cambodian people "hostage", Sophal said the EU should not back down.

"I think the EU should not be cowed by this and instead redouble its resolve: if the leader of a small country threatens to kill the opposition, then it is certifiable proof that he's abusing human rights," he said.