Voters across Russia cast ballots on Saturday on the second day of an election set to formalise six more years of power for President Vladimir Putin, who faces no serious challengers after crushing political dissent over his nearly 25 years of rule.

The election comes against the backdrop of a ruthless crackdown that has stifled independent media and prominent rights groups. Putin’s fiercest foe, Alexei Navalny, died in an Arctic prison in February, and other critics are either in jail or in exile.

Putin faces three token rivals from Kremlin-friendly parties, who have refrained from any criticism of him or his invasion of Ukraine. Putin has cast his war in Ukraine, now in its third year, as an existential battle against the US and other Western powers bent on destroying Russia.

Officials said voting was proceeding in an orderly fashion. But despite tight controls, at least half a dozen cases of vandalism at polling stations were reported Friday and Saturday, including a firebombing and several people pouring green liquid into ballot boxes. The latter was an apparent homage to Navalny, who in 2017 was attacked by an assailant splashing green disinfectant in his face.

Russian state news agency Tass said a woman in the Urals city of Ekaterinburg on Saturday tried to unsuccessfully throw green liquid into a ballot box while a pensioner in the Altai region in southern Siberia attempted to damage ballots. Both were detained.