Sam Rainsy was nominated “acting president” of the Cambodia National Rescue Party (CNRP) as the curtain fell on the two-day international conference the former opposition party held in the US over the weekend, a move supporters of the previous leader Kem Sokha blasted as “unacceptable”.

On Monday a pro-Sokha faction issued a statement refusing to “accept” the decision, saying it went against the party’s bylaws.

“The CNRP confirms that the party’s Permanent Committee does not have to follow [this] decision made at the conference because [those involved] do not have the right to act as either requester or selector in choosing an acting president. Therefore, this decision is just a comment from a small group of people,” the statement said.

International CNRP leadership in support of Kem Sokha, including from the US and Australia, boycotted the weekend conference.

Kem Sokha is currently on bail awaiting trial on treason charges.

Sam Rainsy, a co-founder of the CNRP along with Kem Sokha, fled to France years ago, stepping down as party president to avoid a slew of criminal convictions. He launched the Cambodia National Rescue Movement in January.

According to the three-page report outlining the decision and signed by Suy Seng Hong, who headed the conference, Rainsy was nominated “acting president of the CNRP” for the period in which Sokha cannot lead the party.

Article 3 of the report stated: “The position of acting president will expire once Kem Sokha gets full freedom and is able to lead the CNRP.”

Speaking after the decision, Rainsy thanked his supporters and accepted the position, claiming the party’s structure remained intact.

“First point, as I agree to take the position as people requested, we do not touch the CNRP’s structure, especially that Kem Sokha is still president."

“Second point, the acting president’s position will [cease to exist] once Kem Sokha gets complete freedom."

“Third point, if I hold this position, we all need to work together and CNRP supporters have to unite and work together under the theme ‘Kem Sokha and Sam Rainsy are one person’."

“I would like to appeal to all CNRP supporters to unite. If I hold this position, it means that our CNRP is intact. No former Sam Rainsy Party, no former CNRP; no pro-Kem Sokha, no pro-Sam Rainsy,” he said.

Both Sokha’s daughters – Kem Monovithya and Kem Samathida – took to Facebook on Sunday.

“History will record the names of the participants who destroyed the forces of the patriots,” wrote Samathida, Sokha’s second daughter.

Monovithya, the former CNRP deputy director-general of public affairs and Sokha’s eldest daughter, said on Facebook and Twitter: “It is not the first time that evil individuals have tried to harm Kem Sokha, but they keep failing.”

Ruling Cambodian People’s Party spokesman Sok Eysan mocked Rainsy’s nomination as CNRP acting president, dismissing the move as “useless”.

“Sam Rainsy, the former opposition party leader, resigned from its membership and as party leader a long time ago. Therefore, this trick in attempting to resurrect the opposition party is impossible. This attempt to help Sam Rainsy lead the former opposition party is also useless,” he wrote on Telegram on Monday.

Analyst Meas Nee said the nomination of Sam Rainsy as CNRP acting president risked “splitting” the opposition.