Cambodia sentenced exiled opposition figure Sam Rainsy to life imprisonment on Wednesday for allegedly attempting to cede territory to a foreign entity, according to a court ruling.
The case related to the politician's promises to protect the rights of the country's indigenous people, who continue to face discrimination mostly over land rights.
A document from the Phnom Penh Municipal Court -- seen by AFP -- said Rainsy had been "sentenced to life imprisonment on charges of attempting to hand over a part of national territory to a foreign entity" in 2013.
The court also stripped him of all political rights, it added.
It relates to a 2013 meeting between Rainsy and a leader of the US-based Montagnard Foundation, which works to protect the rights of indigenous minorities in Vietnam.
A video posted by an anonymous Facebook account in 2018 appeared to show him pledging to uphold the rights of Cambodia's indigenous people.
Rainsy and the Montagnard Foundation's then-leader Kok Ksor also signed a document with three articles from the United Nations Declaration on the Rights of Indigenous Peoples on minorities' self-determination rights.
But Cambodian authorities accused him of treachery, and of attempting to give land to foreigners.
Montagnard people are a mostly Christian ethnic minority group that lives in Vietnam's mountainous Central Highlands region.
Rainsy has lived in France since 2015 to avoid jail on a number of convictions he says are politically motivated, including a 25-year sentence passed in March last year.
Strongman Prime Minister Hun Sen on Monday said Rainsy's family have been traitors to Cambodia.