An Iranian-British woman detained while trying to attend a men's volleyball game has been sentenced to one year in prison, her lawyer has said.

Mahmoud Alizadeh Tabatabaei told the Associated Press news agency on Sunday that a court found Ghoncheh Ghavami, 25, guilty of "propagating against the ruling system".

Tabatabaei said he was shown the text of the verdict but was still waiting to officially receive it.

We have concerns about the grounds for this prosecution, due process during the trial, and Miss Ghavami's treatment whilst in custody. British Foreign Office

In a statement on Sunday, the British Foreign Office cited concerns about Ghavami's conviction and sentence.

"We have concerns about the grounds for this prosecution, due process during the trial, and Miss Ghavami's treatment whilst in custody," the statement noted.

Ghavami was detained in June at Tehran's Freedom Stadium, where Iran's national volleyball team was to play Italy.

Hunger strike

Iranian officials have said Ghavami, who has been held in the capital's notorious Evin Prison for 126 days, was detained for security reasons unrelated to the volleyball match.

"Her case has nothing to do with sports," Iran's judiciary spokesman, Gholam Hossein Mohseni Ejehi, said last month.

Women are banned from attending male-only matches in Iran and Ghavami tried to enter the match with other women to protest the ban, according to Amnesty International. Some were reportedly turned away, but no others were arrested.

The "Free Ghoncheh Ghavami" Facebook page, where her friends and family campaigned for her release, features photographs of her against the slogan: "Jailed for wanting to watch a volleyball match."

Ghavami has been held in solitary confinement since her arrest, according to Amnesty, and she began a hunger strike earlier this month to protest her detention.

Iran does not recognise dual citizenship and treats dual nationals as Iranians.