WASHINGTON: US Secretary of State Hillary Clinton on Wednesday criticised Russia for effectively banning an opposition party known for its fierce criticism of Prime Minister Vladimir Putin.

In a statement, Clinton said “the United States is disappointed by the refusal of the Russian Ministry of Justice to register” the People's Freedom Party, known in Russian under its acronym Parnas.

The move denies the party an opportunity to take part in upcoming polls for the Duma, or parliament.

“We are troubled by reports of pressure from authorities in the regions designed to intimidate Parnas supporters, prompting them to resign positions or disavow their signatures on required lists,” the chief US diplomat said.

“The right to hold free, fair, competitive elections is a universal principle that the Russian government has repeatedly endorsed,” she added.

“It is hard to understand how this decision today by the Ministry of Justice is consistent with Russia's international commitments and recent statements by Russia's own leaders,” said the secretary.

“We urge the authorities to investigate the reports of irregularities in the Parnas registration process to ensure that the procedures used to deny registration of this party were consistent with Russian laws and international standards.”

The decision by the justice ministry surprised few in Russia, where it is seen as a litmus test of the Kremlin's willingness to tolerate dissenters ahead of crucial parliamentary polls in December and presidential elections in March.

Last month, former Prime Minister Mikhail Kasyanov, former deputy prime minister Boris Nemtsov and several other politicians submitted documents to register a new opposition party they dubbed the People's Freedom Party.