By Jon Leyne
BBC News, Tehran
Ms Momeni is detained in the notorious 'Unit 203' for political prisoners
There is growing concern about the fate of an Iranian-American student who has been detained in Iran.
Esha Momeni, who is from Los Angeles, was doing research into the status of women in Iran when she was arrested on 15 October.
According to her lawyer, Ms Momeni, 28, was pulled over for a traffic offence in the capital, Tehran.
She is now being held in the notorious Evin prison near Tehran, which houses a number of political activists.
The authorities have not said why she is being held, though it may be related to the "One Million Signatures Campaign", in which women in Iran are pressing for more rights.
At the time of her arrest, police confiscated some film she had taken and also raided the place where she was staying, seizing some of her belongings.
Her lawyer has not been allowed to meet her and she has had just one telephone conversation with her family.
Last year, several Iranian-Americans were held for some months.
The Iranian government believed they were working for a so-called "Velvet Revolution", though no charges were ever brought and they were eventually allowed to return to the United States.