It's time for the United States to hold Iran accountable.

Two dual US-Iranian citizens have both been sentenced to 10 years in jail in Iran for collaborating with the US government, the state-run Mizan judicial news agency has reported.

Siamak Namazi, a businessman, was detained by Iran's Islamic Revolutionary Guard last October.

His father Baquer, 80, was detained in February while seeking his release.

The US State Department says it is deeply concerned about the sentencing reports.

"We join recent calls by international organizations and UN human rights experts for the immediate release of all US citizens unjustly detained in Iran, including Siamak and Baquer Namazi, so that they can return to their families," spokesman Mark Toner said.

There are no precise details of the charges for which the pair were convicted.

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