MOSCOW (AP) — Russian opposition leader Alexei Navalny says his brother is being illegally kept in prison despite a European court decision.

Navalny said in a statement Tuesday that he has appealed to the Russian Supreme Court to seek his brother's release.

Oleg Navalny was sent to prison in 2014 on fraud charges seen by many as an attempt to punish Alexei Navalny, an opponent of Russian President Vladimir Putin.

The European Court of Human Rights ruled in October that Russian courts handed down "arbitrary and manifestly unreasonable" decisions in the case.

Though disagreeing with the ruling, the Russian Justice Ministry is meant to abide by it.

It's unclear why Oleg Navalny has not been released.

Alexei Navalny was banned from Sunday's election which saw Putin win another six years in power.