PHNOM PENH (Reuters) – The United States renewed a call for Cambodia’s government to release the country’s main opposition leader Kem Sokha from prison, after parliament voted to change election laws that would re-distribute his party’s seats if it was dissolved.

The government is seeking to dissolve Kem Sokha’s Cambodia National Rescue Party (CNRP), arguing he and his party sought to topple the government, a move which would help Prime Minister Hun Sen extend his 32-year rule at the next election in 2018..

The U.S. State Department said Washington was “deeply concerned” by parliament’s passage of the amendments and if ratified “would effectively disenfranchise the millions of people who voted for the CNRP in the 2013 and 2017 elections”.

“Genuine competition is essential to democracy and to the legitimacy of the 2018 national elections,” U.S. State Department spokesperson Heather Nauert said in a statement released in Cambodia on Tuesday.

“We urge government officials to consider the serious implications of their recent actions. We renew our call that the leader of the CNRP, Kem Sokha, be released from prison.”

A spokesman for Cambodia’s ruling party said the U.S State Department’s statement was weak and Cambodia was on the right track to towards a free and fair election next year.

“Their tone is lighter. Before, they would bully so this means we are on the right path towards democracy and rule of law,” Sok Eysan, a parliamentarian from Hun Sen’s ruling Cambodian People’s Party (CPP), told Reuters.

Cambodia’s National Assembly voted on Monday to change election laws to re-distribute seats to other parties in parliament within seven days of a party being dissolved.

Lawyers from the interior ministry filed a lawsuit on Oct. 6 to demand the dissolution the CNRP, after Kem Sokha was charged with treason following his Sept. 3 arrest.

The government has said CNRP conspired with foreign advisors to topple the government, citing a 2013 video clip showing Kem Sokha talking about a plan to take power with the help of Americans.

Half of opposition figures fled abroad in September and early October as Hun Sen moves to tighten his grip on power by silencing critics in the lead-up to the national election.

Mu Sochua, deputy president of the opposition CNRP, who fled Cambodia earlier this month in fear of arrest, called on political parties to only contest the 2018 election if it is free and fair.

“All conditions for free fair and inclusive elections must be met,” Mu Sochua told Reuters. “Any party that want to compete to win CPP must only do so if these conditions are met.”