The state-run Thanh Nien daily reports that Tim Sakhorn, a member of the exiled Khmer Kampuchea-Krom Federation, has been taken into custody, accused of undermining national unity by organising anti-Vietnam demonstrations in Cambodia, accusing the Hanoi government of repressing ethnic Khmers.

The 39 year old Vietnamese national disappeared several weeks ago in neighbouring Cambodia.

A former abbot in Cambodia, he was defrocked in late June and disappeared amid unconfirmed reports he was detained by Cambodian authorities for deportation to Vietnam.

The arrest comes in the same week that police in Phnom Penh charged two ethnic Cambodian men from southern Vietnam with terrorism over last weekend's failed bombing of the occupation-era Cambodia-Vietnam friendship statue in Phnom Penh.