Phnom Penh, Sep 5 (IANS): Cambodian opposition leader Kem Sokha was formally charged with treason on Tuesday, two days after he was arrested in a raid that was criticised by the UN and other international organisations.

A Phnom Penh Municipal Court spokesperson said there were enough legal grounds to charge the 64-year-old with conspiring against the government with a foreign power, reports Efe news.

"He has been accused of treason, which carries a prison term of between 15 to 30 years, based on a video of a speech he made in 2013 and which has been publicly available since then," UN High Commissioner for Human Rights Zeid Ra'ad al-Hussein said.

"I am seriously concerned at the arrest, which appears to have been carried out with no respect for due process guarantees, including respect for his parliamentary immunity."

He also expressed concern that numerous public statements made by Prime Minister Hun Sen and other officials "breach the presumption of innocence and the right to a fair trial".

The government had also recently shut down the offices of the Washington-based non-profit National Democratic Institute as well as 19 radio stations and the newspaper Cambodia Daily.

The Cambodian parliamentary elections will take place on July 29, 2018, and for the first time the Cambodian People's Party, led by Hun Sen who has been the Prime Minister since 1985, has not emerged as a clear favourite.