Russian officials cancel registration of opposition leader Navalny's Progress Party

Russian officials have cancelled the registration of the political party led by Alexei Navalny, the anti-corruption activist who is one of President Vladimir Putin's most adamant critics.

The Justice Ministry said Tuesday that the Progress Party had not fulfilled a requirement to register operations in at least half of Russia's regions.

It was unclear if the ministry decision would affect Progress' intention to field candidates in regional elections this year. The party recently announced it was establishing a coalition with the opposition RPR-PARNAS party. That party's leaders included Boris Nemtsov, who was shot dead in February.

Another RPR-PARNAS leader, Mikhail Kasyanov, said the coalition was created "in consideration of any possible actions by the authorities and we will use all means to overcome difficulties," according the Tass news agency.