Iran's semi-official ISNA news agency is saying an Iranian-British woman has been detained because of her links to the opposition, not just for attending a volleyball match.

The Tuesday report quotes a statement by the Tehran prosecutor's office as saying Ghoncheh Ghavami was active in opposition protests against the ruling establishment abroad, and was in contact with foreign satellite channels such as the BBC Farsi service.

Ghavami was detained in June after trying to attend a men's volleyball match between Iran and Italy, in defiance of hard-liners' push for gender-segregation. Earlier in November, her lawyer said that a court sentenced Ghavami, 25, to one year in prison after finding her guilty of "propagating against the ruling system."