Thirty-one French nationals from the same tour group in Cambodia tested positive for the coronavirus over the weekend and have been put under quarantine in a hotel.
The tourists -- ranging in age from late 40s to 80 -- were part of a group of 36 that arrived on March 11 in Siem Reap, home to the famed Angkor Wat temple complex.
The patients are currently receiving treatment in isolation in the southern coastal city of Sihanoukville.
Two local guides also tested positive for the virus, while the remaining five tourists tested negative, the health ministry said Sunday.
Including the tour group cluster, Cambodia has reported 87 COVID-19 cases, as the pandemic that has killed more than 15,000 sends the world into chaos.
Cambodian authorities have shuttered entertainment venues like karaoke bars, and schools were requested to close, but there has been no official order for people to stay home.
Last week Cambodia issued a blanket ban on foreigners entering the country from France, the US, Italy, Spain, Germany and Iran.
Strongman premier Hun Sen has vociferously stood behind China, where the new disease originated late last year.
On Monday, Chinese experts arrived in Phnom Penh ferrying medical supplies to "jointly fight against COVID-19", the health minister said.
Cambodia receives billions in aid, infrastructure loans and investment from China, and has long regarded it as a valuable ally as Western donors receded due to alleged human rights abuses by Hun Sen's government.