PHNOM PENH, Cambodia — A prominent opposition lawmaker in Cambodia has fled the country, saying Wednesday that Prime Minister Hun Sen made direct threats against her and her colleagues and that she no longer felt safe in her own country.

Mu Sochua, who serves as deputy president of the Cambodia National Rescue Party, left Cambodia on Tuesday, a day after Hun Sen warned of strong action against any other politicians who may have been involved in opposition leader Kem Sokha’s alleged plot to overthrow the government. Kem Monovithya, the party’s deputy chief for public affairs, said on Twitter late Tuesday that Mu Sochua had received a warning from a senior Interior Ministry official that she would be arrested.

Opposition party president Kem Sokha was charged with treason for allegedly conspiring with the United States to topple the Cambodian government, and could face up to 30 years in prison if convicted. He was arrested on Sept. 3 on the basis of videos from several years ago showing him at a seminar where he spoke about receiving advice from U.S. pro-democracy groups.

His arrest in the middle of the night came amid a crackdown on the media.

Almost half of the 55 opposition lawmakers have fled Cambodia since Kem Sokha’s arrest, fearing for their own security and to avoid being arrested themselves. Mu Sochua’s whereabouts were not immediately known.

“The situation is very serious and has direct impact on 2018 elections,” Mu Sochua said Wednesday in a text message to The Associated Press. “I no longer feel safe inside the country. My voice needs to be heard inside and outside. Leaving Cambodia is not a choice, but surviving imminent arrest is necessary.”

Kem Sokha had been expected to lead his Cambodia National Rescue Party in next year’s election in a strong challenge against the Cambodian People’s Party of Hun Sen, who has held power for three decades. The opposition party has denied the treason allegation, saying the charge is strictly politically motivated.

In a speech in Siem Reap province on Monday, Hun Sen said treasonous acts within the opposition involved other opposition party officials in addition to Kem Sokha. He said he would search for those who may have been involved.

Cambodia’s appeals court last week rejected a request for the release on bail of Kem Sokha. On Tuesday, Kem Sokha released a statement denying the accusations, saying he has always sought “change through nonviolent elections” in his role as opposition party president.

“It’s not surprising that Mu Sochua is fleeing these threats by newly minted dictator Hun Sen because no one doubts he can order instant violence by the military and police, and controls all the levers in Cambodia’s kangaroo courts,” said Phil Robertson, deputy Asia director of New York-based Human Rights Watch.