PHNOM PENH • Sam Rainsy resigned from the presidency of Cambodia's leading opposition party yesterday, shortly after Prime Minister Hun Sen threatened legal changes that appeared to target his main opponent ahead of polls.

Mr Hun Sen said this month that a law was being amended to stop anyone convicted of an offence from running for office for five years, effectively barring his main rival from elections.

Courts that critics say are influenced by Mr Hun Sen have convicted Rainsy of a series of defamation charges, forcing the opposition leader into exile in France.

Mr Hun Sen's proposed changes to a 1998 law would also open up the possibility of political parties being dissolved if a leader is convicted of a serious crime.

Rainsy announced his surprise decision to step down from the leadership of the Cambodia National Rescue Party (CNRP) on his social media accounts yesterday.

He said he was quitting for "personal reasons" and did not directly link his resignation to the proposed legal amendments.

"I resign as CNRP leader for the sake of the party," he wrote on Twitter. "In all circumstances, I cherish and uphold the CNRP's ideals in my heart."

Cambodia holds local elections in June and a general election next year. Opponents accuse Mr Hun Sen of manoeuvring to try to extend his rule.

Rainsy has not entered the country since 2015, and faces years in prison if he returns.

His deputy, Mr Kem Sokha, who has been serving as CNRP's acting leader in Rainsy's absence, is expected to guide the party as it prepares for the elections.

REUTERS, AGENCE FRANCE-PRESSE