Cambodian-Americans from Southern California held a peaceful protest in front of Long Beach City Hall on Saturday to urge the Cambodian government to release opposition leader Kem Sokha and to call for the United Nations to intervene in the country’s currently tense political situation ahead of next year’s national elections.

Boone Ran, 45, who fled to the US with his mother after his father was killed during the Khmer Rouge era, was among those who took part in the demonstration, which drew hundreds of protesters.

Ran said he attended the protest to show his support for Sokha. “We ask Hun Sen, we plead him,” he said. “We ask him to release [Sokha]. If not, we are not going to have free elections. We need to repair our country, which is in deep trouble.”

Sokha was arrested earlier this month and charged with treason after a four-year-old video, in which he says he received advice from the US on how to build his political career, resurfaced online. Senior government officials have claimed Sokha received assistance to instigate a “colour revolution” in the country. The arrest has been widely condemned both in Cambodia and abroad.

Ran, like many others at the protest, said he was concerned with the government’s recent actions, which have also included a crackdown on independent media and an escalation of anti-US rhetoric.

He attributed the recent moves to the ruling party’s fear of losing the 2018 national elections, in which Sokha’s Cambodia National Rescue Party represents its only legitimate challenge. “[Hun Sen] is afraid, and he will do whatever he can to destroy the parties that go against him,” he said. “I believe that he realises that his time is coming.”

James Heng, 44, who also moved to the US during the years of civil war in the Kingdom, said he would also like to see the Cambodian government release Sokha as the accusations and charges are “baseless and ridiculous”. “It’s all politically motivated,” he said. “’They know they will lose the 2018 elections.”

Heng said Cambodians living abroad hoped for an international intervention, such as when the UN organised the 1993 elections.

Tongratha Veng, one of the protest organisers, said the rally was organised to send several messages, including calling for the release of other political prisoners. “My biggest concern is that Cambodia will slip back into communism,” he said.

Veng said the US should pressure the Cambodian government through trade sanctions, visa bans and even revoking citizenship of government officials, especially since the US is involved in the accusations of helping Sokha overthrow the Cambodian government.

“We really hope that the US will help,” he said, later adding that Cambodians should “prepare for the worst”.