By arresting Iran’s top human rights lawyer, Nasrin Sotoudeh, powerful Iranian hard-liners are aiming to silence the most prominent voice for the voiceless in the Islamic republic.

​Sotoudeh’s husband, Reza Khandan, has said that she was rearrested at her home on June 13 to serve a five-year prison sentence on unknown charges. He said she didn’t know anything about the sentence.

The London-based human rights group Amnesty International condemned her latest detention, calling it an "outrageous attack on a brave and prolific human rights defender."

The United States said it was "deeply concerned" by reports of Sotoudeh's rearrest.

"First arrested in 2010, Ms. Sotoudeh has spent the past several years harassed by the Iranian regime and has been routinely placed behind bars for daring to defend the rights of those in Iran," spokeswoman Heather Nauert said in a statement. "We applaud Ms. Sotoudeh’s bravery and her fight for the long-suffering victims of the regime. We call on Iranian authorities to release her immediately, along with the hundreds of others who are currently imprisoned simply for expressing their views and desires for a better life."

Sotoudeh, 55, has been among a handful of rights advocates and activists who have stood up against state repression and highlighted human rights abuses in the country.

In 2010, Sotoudeh was sentenced to six years in prison -- reduced from an initial 11-year sentence -- and a 10-year ban on practicing law for several charges, including acting against Iran's national security.

She spent three years in prison before being released unexpectedly in 2013 ahead of a trip to New York to attend the UN General Assembly by the then newly elected president, Hassan Rohani.

In 2012, the European Parliament gave its most prestigious award, the Sakharov Prize for Freedom of Thought, to Sotoudeh and acclaimed Iranian filmmaker Jafar Panahi.

These are some of the sensitive political cases Sotoudeh has represented and the issues she has raised in recent years:

Defending Anti-Hijab Protesters

In the past several months, Sotoudeh had been defending several young women who peacefully protested the compulsory hijab rule in Tehran by removing their head scarves in public and waving them on sticks while standing on utility boxes.

Sotoudeh had represented them in courts while also raising their plight in media interviews and by providing details about the cases on her Facebook page. She also criticized the use of force against some of the women, whose protests were forcefully stopped by police.

“The women of our land are flowing like rivers,” she wrote in a February 22 post on Facebook.

“Don’t jail them, don’t put them on trial, they haven’t committed any crimes,” Sotoudeh said, while adding that Iranian women “want to be in charge of deciding about their clothing.”

Criticizing An Official List That Excludes Most Lawyers From Politically Charged Cases

Sotoudeh had in recent weeks spoken out against a Judiciary-approved list of lawyers who will be allowed to represent individuals accused of national security, political, and media offenses.

She and others who have defended political prisoners were not on the list.

Sotoudeh told RFE/RL last week that political detainees in Iran will be “completely” denied the right to defense due to the list.

“The plaintiff in political cases is either the Intelligence Ministry or the Islamic Revolutionary Guards Corps, meaning it’s either a security body or a military one -- and both incite fear and intimidation for the defendants," Sotoudeh said.

Calling For A UN-Held Referendum On A New System Of Government In Iran

Earlier this year, the outspoken mother of two signed a public statement calling for a referendum, organized by the United Nations, that would pave the way for a new system of government in Iran.

The statement said the current system -- which it accused of systematic rights violations, corruption, and the selective use of religion -- has become the "main obstacle to the progress and liberation of the Iranian people.”

Sotoudeh and the other 14 signatories of the statement said they favor “a peaceful transition from the Islamic republic to a secular parliamentary democracy” that would be based on freedom of expression, respect for human rights, and the elimination of all discrimination and equality, particularly for women.

Defending Child Offenders On Death Row, Women’s Rights Activists, And Intellectuals

Before her arrest in 2010, Sotoudeh defended some of those arrested in the state crackdown that followed the disputed 2009 presidential election. She also presented the cases of several child offenders on death row, women’s rights activists, journalists, and others charged in politically motivated cases.

Sotoudeh had been campaigning against the death penalty in Iran, which executes more prisoners than almost any other country in the world.

She was also a member of the One Million Signatures Campaign, which aimed to gather support for the elimination of laws that discriminate against women, including in divorce and child custody.

Hope Followed By Despair

While her 2013 release was viewed as a very hopeful sign, her rearrest on June 13 is likely to have a chilling effect on those pushing for change in the Islamic republic.

It comes amid a U.S. withdrawal from the 2015 nuclear deal, which appears to have empowered powerful hard-liners in charge of key institutions, including the judiciary.

In a May 9 interview with RFE/RL, Sotoudeh predicted that U.S. President Donald Trump’s decision to quit the deal would likely contribute to a worsening of Iran's domestic rights situation.

“The end of diplomacy and negotiations can lead the international community toward war. As a matter of fact, when the country faces a war situation, any talk of human rights is meaningless,” Sotoudeh told RFE/RL from Tehran.