On Wednesday, imprisoned activist Alexei Navalny began a hunger strike to protest the unfair treatment he has received as an inmate of a penal colony outside Moscow. But while Navalny's hunger strike highlights the shameful handling he has been subjected to, there is much that can be done from outside his cell. That's why we must go on a hunger strike in solidarity.

Navalny claims he has been denied proper attention for severe pain and harassed by staff at the prison, which he describes as "a real concentration camp 60 miles away" from the Russian capital.

It's no surprise that Navalny, President Vladimir Putin's most popular critic, has suffered this sort of mistreatment. Only last August, the Kremlin tried to kill him with poison. And ever since his return from Germany, where he fled to recover from the botched assassination attempt, he has been a political prisoner of the Russian state.

But none of that has stopped him from launching the largest wave of protests his country has seen in a decade, or from publishing a damning investigation into Putin's private wealth. Even behind bars, Navalny remains a thorn in Putin's side.

Until Navalny is free, the tide of our discontent will not be stopped. In solidarity with the Navalny and the anti-Putin movement, renounce all food until all of Putin's assets are frozen, sanctions are imposed on his autocratic regime — and Navalny is justly freed.

Give Putin — authoritarian thug and criminal "killer" — his just deserts. Go on a #HungerStrikeForNavalny and #KickPutinsAssets.