The new death toll suggests fighting is some of the worst seen in the region in years.
Cambodia PM Hun Sen, Lao counterpart Thongloun Sisolith hold second meeting since border flare up.
Attendees at an enforced 'symposium' receive no reply to queries about 'disappeared' colleagues, while being warned not to speak to foreign media about their cases.
More than 27,000 Rohingya have crossed into Bangladesh from Myanmar within the past seven days, diplomatic sources say.
They say the government’s measures are ‘deeply concerning' for the fate of Cambodian democracy.
The pair, who had been jailed before, were convicted most recently under Article 79, a broadly worded national security law.
President Xi Jinping is expected to reveal the lineup at the highest levels of government, and the list of names will show whether any other faction in the ruling party still has a voice.
Authorities in the northwestern region of Xinjiang have detained dozens of Kazakhs in a crackdown on devout Muslims or those with links overseas since May.
About 18,000 Rohingya crossed into Bangladesh in the last week, the IOM says.
The announcement follows recent moves to limit foreign broadcasting and restrict opposition voices in the country.
Rural development expert Sombath Somphone has been unaccounted for since December 2012 and the Lao government has not been forthcoming about his case.
Peaceful dissidents, lawyers and rights activists are frequently held incommunicado under laws governing "matters of state security."
