Two Australian-British women and an Australian man have been detained in Iran and are being held in a notorious prison in the capital of Tehran.
One of the women, a blogger who was travelling through Asia, and her Australian boyfriend were arrested about 10 weeks ago on charges which remain unclear, The Times of London reported on Wednesday.
The other woman, an academic who had been lecturing at an Australian university, has been given a 10-year sentence.
While the charges against her also remain unclear, 10-year terms are routinely given in Iran for spying charges, the Times reported.
However, the ABC on Wednesday claimed this woman had already been held in Iran for "almost a year".
The women and the man are incarcerated in the Evin jail in Tehran where 41-year-old Nazanin Zaghari-Ratcliffe, a British-Iranian mother of one, has been held on spying charges since 2016.
The notorious prison is where Iran holds its political prisoners and has a reputation for the scene of various human rights abuses, including summary executions.
The cases of the women, who are dual citizens, are believed to be the first imprisonments in Iran of British passport holders who do not also have Iranian nationality.
The arrests come amid a downturn in relations between Britain and Iran, sparked by issues including the seizure by the Royal Marines in July of an Iranian oil tanker near Gibraltar.
The blogger and her boyfriend had been documenting their travels on YouTube and Instagram.
Concerns were raised by their online followers when they failed to add any news posts in the past several weeks.
The Foreign and Commonwealth Office referred the PA news agency's request for comment to the Australian Department of Foreign Affairs and Trade, which has yet to respond.
"Due to our privacy obligations, we will not comment further," a spokesman for the Department of Foreign Affairs and Trade told AAP on Wednesday.
"All Australian citizens and holders of dual nationality with Australia who are travelling to or through Iran are urged to follow the travel advice on the DFAT Smartraveller website."
Australian citizens have long been advised to reconsider plans to travel to Iran because of a "risk that foreigners including Australians could be arbitrarily detained or arrested".
In August, Prime Minister Scott Morrison announced Australia would join a US-led coalition to protect commercial shipping vessels in the Strait of Hormuz after a number of boarding incidents by Iranian actors.
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