Dear abdoukarim,

The world has watched with shock and a profound sense of dismay the scenes of bloody, rampant violence that have filled the streets of Tehran and other cities in the wake of Iran's hotly contested presidential elections.

But behind the scenes, Iranian authorities are conducting a simultaneous effort aimed at silencing dissident voices through arbitrary arrests and detention.

Plain clothes Iranian security officials have arrested leading human rights activist Abdolfattah Soltani and have rounded up countless other students, opposition politicians, journalists and rights activists and thrown them in prison.

Soltani has for years stood by individuals who have suffered repression in Iran. And by putting himself in the line of fire, he too has become a target of the Iranian government's brutal repression.

Amnesty first took up Soltani's case in 2005, when he was arrested for representing other victims of human rights violations. Since then, Soltani has endured both imprisonment and solitary confinement for bravely challenging repression and demanding respect for human rights in Iran.

But thanks in part to letters from Amnesty supporters, he was released on bail in 2006 and acquitted in 2007 of the fabricated charges against him.

The Iranian government is doing everything in its power to crush the spirit of resistance that has challenged its authority.

Its aim is not only to silence rights defenders like Soltani through imprisonment, but create a chilling effect to discourage others from standing up for human rights.

We can't let that happen. Please call on authorities in Iran today and demand Soltani's immediate release.

By doing so, you'll help counter the climate of fear instilled by Iranian authorities with a spirit of hope.

What's more is that you'll be sending a vital message of solidarity to Soltani and other human rights defenders like him, reminding them that they are not alone.

Thank you for standing with human rights defenders in Iran --

Elise, Zahir, Christoph and the rest of the Iran crisis response team