US-Iranians jailed by Iran for 10 years

Iranian-American consultant Siamak Namazi was arrested in October 2015

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 organisations 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.

Baquer Namazi's family say there are big questions about his health

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

However the New York Times reported on Monday that a video posted online by Mizan "hinted" that Siamak Namazi was accused of espionage.

"Siamak Namazi and Mohammad Baquer Namazi have each been sentenced to 10 years prison... for co-operating with the hostile government of America," the Mizan website said, quoting "an informed source".

Analysts see the sentences as part of an intensifying campaign by Iranian hardliners against nationals with ties to the West following the historic nuclear deal with the US and other world powers last year.

The family of the two men have protested their innocence and expressed concern that Baquer Namazi has a heart condition which requires special medical attention.

Washington Post journalist Jason Rezaian is suing Iran for ill-treatment he says he suffered while in prison there

Siamak Namazi was most recently working for Crescent Petroleum in the United Arab Emirates, and previously headed a consulting business in Iran.

His father was a former Iranian provincial governor and Unicef official. More recently he ran Hamyaran, an umbrella agency for Iranian non-governmental organisations.

Sources say that a US-Lebanese national, Nazar Zaka, who was reported to have been arrested in November 2015 for suspected espionage, was also jailed for 10 years on Tuesday.

In January Iran released Washington Post journalist Jason Rezaian who spent nearly two years in prison on espionage charges. He was freed at the same time as a nuclear accord came into force, lifting sanctions against Iran.

Rezaian is now is suing Iran's government for "irreparable harm" he allegedly suffered while in prison because of "torture and other cruel treatment".