The Human Rights Party rebuked authorities for allowing an opposition inflation demonstration Sunday, claiming the government had been unfair in denying permission to hold a gathering on fuel prices in February.

The Sam Rainsy Party, the only opposition party with seats in parliament, gathered several hundred demonstrators in Phnom Penh Sunday to protest high inflation rates.

The Human Rights Party said it had been denied a similar demonstration in February. The statement was a further separation of the two parties ahead of elections.

The Human Rights Party was formed by former rights advocate and politician Kem Sokha, following commune elections last year.

"HRP cannot accept the discrimination, bias and inequality of rights and freedoms made by the government for political parties," Keo Remy, vice president of the Human Rights Party, said Monday. "Because this opposes the principals of the law and democracy."

The party members "condemn the government for violating the law," he said. "The Human Rights Party asked the authorities for a public forum to find a way to reduce the price of fuel, but the government and authorities denied this. But why, if Sam Rainsy asks for a demonstration, does the government allow the Sam Rainsy Party to do it? We question what's behind the permission."

Cambodian law provides for the freedom of assembly, but the government is often criticized for preventing marches and demonstrations.

The city "had no secrecy behind the Sam Rainsy permission to hold a demonstration," Phnom Penh Deputy Governor Pa Socheatvong said Monday. 

"The Sam Rainsy Party proposal for public expression was clear, but the HRP proposal for a public forum we didn't understand clearly their purpose," he said.

Ny Chakriya, an investigator for the rights group Adhoc, said the government had violated the law by not allowing the HRP gathering in February.

Sam Rainsy said Monday his demonstration Sunday had been allowed thanks to pressure from US Ambassador Joseph Mussomeli.

Armed forces prevented some from joining the rally, he added.

"The Sam Rainsy Party will hold the next demonstration without asking permission from the authorities, by walking into the public street," he said.

US Embassy spokesman Jeff Daigle said Monday the ambassador had called on "all interested parties" to work together for the right of "peaceful assembly," but had not "pressured" the government.