Former US President Barack Obama has described Alexei Navalny as "a fearless advocate for his beliefs who died unbroken by the tyranny he opposed".
Obama's statement went on: "He fought corruption, inspired millions and never wavered in his insistence on free expression, the rule of law, and a Russia that is accountable to the people and not a dictator.
"He died in unyielding defence of his vision of a better future for his country - a vision, and a courageous example, that will never die."
