Hun Sen, who came to power in 1985 in a country still plagued by civil war, has cracked down on dissent in the run-up to this year's poll.
The son of Cambodia's long-serving Prime Minister was promoted to two senior military posts on Saturday as his father looks to widen his family's influence.
Cambodia's prime minister on Saturday accused the US government of being dishonest in its announced suspension of aid to the Southeast Asian nation, saying Cambodia had already stopped receiving aid from Washington in 2016.
Thousands of Cambodian survivors of the Khmer Rouge on Sunday marked 39 years since the fall of the brutal regime that killed an estimated 1.7 million people.
Cambodian Prime Minister Hun Sen challenged the United States on Sunday to cut all aid after it announced it was ending funding for a general election next year in response to the dissolution of the main opposition party, media reported.
Cambodian government lawyers filed a lawsuit on Friday to demand the dissolution of the main opposition party, in a move that would help Prime Minister Hun Sen extend his 32-year rule when the poor Southeast Asian nation votes in an election next year.
Cambodian opposition leader Kem Sokha was arrested in a police raid on his home early on Sunday and veteran Prime Minister Hun Sen accused him of treason with the backing of the United States.
Tens of thousands of Cambodians poured onto the streets of Phnom Penh Sunday for the funeral procession of a prominent political analyst murdered in a brazen daylight shooting that shocked the Southeast Asian nation.
A Cambodian court on Wednesday charged an unemployed man with murdering prominent government critic and activist Kem Ley, who was gunned down in broad daylight at a shop in the capital Phnom Penh.
Cambodia's sole passenger train resumed a regular weekend service on Saturday after being suspended for years, with Prime Minister Hun Sen climbing aboard to inaugurate the first trip.