A Cambodian court has sentenced an opposition lawmaker who has been a strong critic of the government's handling of demarcating the border with neighboring Vietnam to 2 1/2 years in prison over online postings he made.

Um Sam An is the latest member of the opposition Cambodia National Rescue Party to be sentenced for making comments on the politically sensitive topic and implying that Prime Minister Hun Sen's government failed to counter land encroachment by Vietnam, Cambodia's traditional enemy.

In handing out the sentence on Monday, Judge Heng Sokna of the Phnom Penh Municipal Court said the accusations made by Um Sam An in Facebook posts last year aimed to cause chaos in society.