The head of Cambodia's opposition party has announced his resignation from the group after the country's long-serving prime minister announced plans for a law that could lead to the party's dissolution.

Sam Rainsy announced his resignation Saturday in a letter to his Cambodia National Rescue Party.

His actions came after Prime Minister Hun Sen earlier this month vowed to amend the laws on political parties to keep convicts from holding leadership positions, among other rules.

Sam Rainsy is in self-imposed exile to avoid a prison sentence for criminal defamation. He's been the target of several lawsuits by Hun Sen and his ruling Cambodian People's Party.

The opposition says the lawsuits are without merit, and just a legal ploy to try to cripple them. Cambodia will hold local elections this June.