The U.S. State Department said on Tuesday it was “deeply concerned” at reports about the sentencing of U.S. citizens Siamak Namazi and his father Baquer Namazi by Iran and called for the release of all Americans being held by Tehran.

“We are deeply concerned about reports that U.S. citizens Siamak Namazi and Baquer Namazi have each been sentenced to 10 years in prison,” State Department spokesman Mark Toner said in a statement.

Iran’s Islamic Revolutionary Guard Corps detained Siamak Namazi, a businessman with dual U.S.-Iranian citizenship, in October 2015, and arrested his father, Basquer, a former UNICEF officials and also a dual citizen, in February.

On the other hand, Iran’s ministers of culture and sport have both resigned, state media reported, the first major change in the cabinet of pragmatist President Hassan Rouhani eight months before presidential elections.

Rouhani’s bid for a second term may prove difficult as many feel the lifting of sanctions under a deal with Western powers to rein in Tehran’s nuclear program, has had no tangible effect on their daily lives. Liberals also accuse him of failing to implement promises of social reform in Iran.

The semi-official news agencies ISNA and Tasnim quoted informed sources as saying Ali Jannati, the minister of Islamic guidance and culture, had resigned.

Jannati came under pressure from conservative clerics when the ministry of culture gave permission to singers to hold concerts in Iran’s most religious cities, Qom and Mashad.

Rouhani’s popularity surged after last year’s deal with world powers that lifted most sanctions on Iran in exchange for curbs on its nuclear program. But that easing has been slow to translate into concrete benefits for Iranians, giving some impetus to conservatives opposed to Rouhani.