The Dragon Gold exercises were held in Kampot province’s Chumkiri district on land controlled by Infantry Brigade 70, an elite reserve force for Prime Minister Hun Sen’s bodyguard unit.
The legislation would allow the US to withdraw, suspend or limit trade privileges Cambodia enjoys.
More than 100 former Cambodia National Rescue Party officials were banned from politics for five years in a Supreme Court decision in November 2017.
Hun Sen and other senior CPP officials have made threats prior to the July 2018 election that the opposition would be “destroyed” or “killed” if sanctions were implemented.
The EU has given Cambodia 12 months to implement reforms or face losing its access to a preferential trade scheme thought to be vital to the economy.
A new U.S. Congress started its work in Washington Thursday with a historic class of new legislators--many without prior political experience.
Prime Minister Hun Sen’s government has called the move to withdraw Cambodia from the Everything But Arms scheme was “has a political motive to drag Cambodia into geopolitical war.”
Sam Rainsy said the large influx of Chinese immigrants to Cambodia, coinciding with a construction boom and waning relations with the West, could lead to a backlash from locals.
Beijing and Washington bicker over history in Cambodia, blaming each other for the rise of the brutal Khmer Rouge regime.
Cambodia also urged the international community not to interfere in its internal affairs and respect its sovereignty.
Sam Rainsy left Cambodia in 2016 facing a number of lawsuits filed by senior officials.