Watch as Joe Biden speaks following the death of Alexei Navalny.

       Russia’s federal prison service said in a statement that Navalny, a 47-year-old politician and anti-corruption campaigner, had died on Friday 16 February.

       According to the agency, he became unwell after a walk and lost consciousness. An ambulance arrived, but he died despite attempts to resuscitate him, it said.

       Kamala Harris, the US vice president, on Friday placed blame for the death of Navalny squarely on the shoulders of Vladimir Putin, leading a string of world leaders who have reacted to the news.

       Ms Harris told attendees at the annual Munich Security Conference that the US government is still working to confirm the facts and circumstances of the death, but called the development “terrible news”.

       Navalny’s wife, Yulia Navalnaya, has warned the Russian president that her husband’s death will not go unpunished.

       “Putin and all those who work for him, his entire entourage, his friends, I want them to know that they will not go unpunished,” she said.