The eight women and three men are said to also include the reformist politician Mohsen Aminzadeh.

Ms Sotoudeh was arrested in 2010 and jailed for six years on charges of acting against national security.

The release of the political prisoners comes just days before Iran's new President Hassan Rouhani visits New York for the UN General Assembly.

In his election campaign, he promised to free political prisoners.

Ms Sotoudeh's husband Reza Khandan wrote on his Facebook page on Wednesday, "Nasrin came... they told her you are free," Reuters reported.

Mr Khandan has not commented further.

Ms Sotoudeh is a well-respected and outspoken human rights lawyer known for taking on high-profile political cases.

Last year she held a 50-day hunger strike in protest at the authorities' treatment of her daughter who was subjected to a travel ban.