Russian opposition leader Alexei Navalny will attend a hearing at the European Court of Human Rights after being granted permission to leave Russia. Authorities had initially barred him from leaving the country.

As reported by Deutsche Welle (DW), Germany’s international broadcaster, the oft-arrested politician was attempting to fly from Moscow to Frankfurt to attend a hearing at Strasbourg’s European Court of Human Rights (ECHR) when he was stopped at Domodedovo airport.

The ECHR is ruling on whether his frequent detentions at the hands of Russian authorities were politically motivated and whether they were legal.

Navalny’s close colleague Vladimir Milov told DW that the decision to stop him leaving was anticipated and meant to stop him speaking on the international stage.

Opposition politician Milov told DW the Kremlin ‘doesn’t want him to give powerful speeches on serious international platforms in the West. I think that is the main reason why they didn’t allow him to leave today. They don’t want him to give a powerful speech in the European Court for Human Rights, which he is capable of doing.”

According to DW, Navalny, a lawyer-turned-political campaigner, has been among the most prominent figures of Russia’s opposition to President Vladimir Putin. He came to prominence in 2008, when his blog exposing malpractice in Russian politics and among the country’s major state-owned companies came to the public’s attention. Revelations published on his blog even led to resignations, a rarity in Russian politics.