Twenty-eight opposition activists were detained in central Moscow on Tuesday, December 31, during an unsanctioned rally calling for the government to uphold the constitutional right to free assembly.

      The rally, which took place on the downtown Triumfalnaya Square, was organized by the activist group Strategy-31, which gathers on the 31st of every month with so many days to defend the Russian Constitution’s Article 31, which grants the right to free assembly.

      The rally wasn't submitted to Moscow authorities' approval, though the local government requires that all rallies of more than one person receive prior permission from City Hall. In their turn, Russian opposition activists say their rallies never receive an approval for various reasons.

      Moscow police reported that 28 people were detained at the Tuesday rally, “despite numerous warnings that the event was unsanctioned,” according to a statement released by the Interior Ministry’s press service.