"Putin, who exercised his arbitrary power by arresting him in increasingly draconian circumstances, is responsible for his death," wrote João Gomes Cravinho on the social network X (formerly Twitter).

Navalny died today, aged 47, in a penal colony in the Arctic, where he had been transferred in December, after being in a prison in the Vladimir region, less than 200 kilometres from Moscow.

The news was released by Russia's prison services, but Navalny's team has not yet confirmed the dissident's death.

"I pay tribute to Alexei Navalny, who resisted Putin's regime and fought for democracy in Russia", added, in his message, the Portuguese MNE, who offered condolences to the family and the Russian people.