A group of political activists were briefly detained Wednesday morning as they undertook a gasoline price survey at O'Russei and Deumkor markets, a party official said.
Thon Vibol, a youth team leader for the Human Rights Party, who led a group of five people to the markets to survey vendors, said they had not been in the wrong.
The team provided a leaflet to market vendors meant to learn more about their views on the rising price of gasoline and goods, he said.
Market security officials detained all five in the team, asking whether they had an official letter from the municipality to perform the survey.
The five people were released after they signed letters of confession with the chairman of the market, Thon Vibol said.
Gasoline prices have shot up in recent months, with the government criticized for doing too little to stop it.
Srun Sron, Prampi Makara district chief, said Wednesday the party activists did not have official permission to distribute a survey.
HRP Vice President Keo Remy said two weeks ago he wrote an official letter to the municipality requesting permission to distribute the survey, but received no response.
Cambodian authorities were biased toward the ruling party, he said.
Phnom Penh Governor Kep Chutema could not be reached for comment Wednesday.