Russian authorities still haven’t announced the cause of death for Navalny.

Under a heavy police presence, thousands of people bade farewell Friday to opposition leader Alexei Navalny at his funeral in Moscow after his still-unexplained death two weeks ago in an Arctic penal colony.

Navalny was buried at a cemetery in the snowy southeastern outskirts of the capital after a short Russian Orthodox ceremony, with vast crowds waiting outside the church and then streaming to the fresh grave of President Vladimir Putin’s fiercest critic with flowers and anti-government chants.

Although riot police set up barricades at both the church and cemetery, no detentions were reported.