Nasrin Sotoudeh, prominent human rights defender, among prisoners freed in Iran

Award-winning human rights lawyer Nasrin Sotoudeh and 11 other political prisoners have reportedly been freed from prison in Iran, according to BBC News.

It was not immediately clear why the eight women and three men, reformist politician Mohsen Aminzadeh reportedly among them, had been released. 

The move comes shortly before Iran's new president, Hassan Rouhani, is set to attend the United Nations' general assembly in New York.

Rouhani has promised to free political prisoners and relax some of the societal and political restrictions strictly imposed in the Islamic Republic.

"It's not a temporary release, it's freedom," Nasrin's husband Reza Khandan told Reuters by phone from Tehran on Wednesday. "They put her in a car and dropped her off at the house."

Nasrin, who represented imprisoned opposition activists in court before being arrested herself, had been in prison since September 2011 and was serving a six-year sentence on charges of spreading anti-government propaganda.

She was awarded the European Sakharov prize for freedom of thought alongside another Iranian in absentia in 2012. The United States has also spoken out publicly on Sotoudeh's behalf. 

Reza Khandan told the Associated Press his wife will follow up on her case in the coming days to find out why she was released. 

"We are all so happy from the depths of our hearts," he told Reuters. "But we are waiting for the last prisoner to leave prison."

Also among those reportedly released Wednesday was Aminzadeh, a key figure in the mass anti-government protests that shook Iran in 2009 and formerly a deputy foreign minister to reformist President Mohammed Khatami.

Aminzadeh had been imprisoned since 2010, according to Russia Today.