Filmmaker Mam Kalyanee told VOA Khmer from the festival that the film was meant to show how development in Cambodia “affects our people’s lives and environment.”
US Embassy spokesman John Simmons confirmed the identities of the men and said they had been evacuated to Bangkok.
A source in Kampong Chhnang said the four were training using a 33-mm rocket when it exploded.
An annual meeting of the Mekong River Commission, which includes representatives of Cambodia, Laos, Thailand and Vietnam will be held in Laos on Jan. 17.
Cambodia will send an eight-member team to Laos on a fact-finding mission over the controversial Xayaburi dam project at the end of the month, officials said Thursday.
The European legislation does not just cover oil and mineral wealth, but is extended to forestry resources as well.
The film follows the lives of three Cambodians, as they grapple with the impacts of development in their rural homes.
Cambodia is now seeking to expand its exports of its jasmine rice and other varieties.
Police say the body of journalist Hang Serei Oudom, 44, was found in the trunk of a car in the remote northeast province of Ratanakkiri.
The low income made by many farmers in Battambang has forced young men to seek work as migrant labor in Thailand.
Villagers here, who are ethnically Khmer or Vietnamese, depend on the fish for daily survival.
Environmentalists say it could have devastating impacts on the Mekong’s fish population, a major food source for millions of Cambodians.