The brother of a British woman locked up in Iran after going to a men's volleyball match has flown to New York to appeal for her release at the United Nations (UN).

Iman Ghavami plans to deliver a petition signed by almost 200,000 people since his sister Ghoncheh was arrested in June to Iranian officials.

The 25-year-old, from Shepherd's Bush in west London, was detained after attending the match and is said to have been held in solitary confinement in Tehran's Evin jail for 41 days before being moved to a shared cell.

She has now spent 85 days behind bars and her brother is hoping to raise her case with Iranian officials as the country's president Hassan Rouhani attends the UN General Assembly in New York.

Mr Ghavami, 28, who arrived in the US city last night, said: "She is suffering for no reason. We miss her and just want my sister home.

"I plan to take my petition to the UN and hope to get two minutes of President Rouhani's time."

A petition he started on the online campaigning platform Change.org titled "Bring my sister home" had more than 194,000 signatures shortly after midday today.

It says Ms Ghavami has dual British Iranian citizenship and "was arrested for going to a men's volleyball match".

"She was there to watch a game," her brother wrote on the petition website. "She was arrested because of a misunderstanding."

He is planning to deliver the petition, which appeals to both the Iranian and UK governments, to the Islamic Republic's UN mission on Thursday.

Ms Ghavami was first held after the match, which took place on June 20, before being released but she was then re-arrested a few days later, according to reports.

Women have been banned from attending volleyball matches in stadia in Iran since 2012, according to Amnesty International.

Foreign Secretary Philip Hammond raised Ms Ghavami's case in a meeting with Iranian foreign minister Mohammed Javad Zarif in the margins of the UN General Assembly yesterday.

He said: "We discussed bilateral relations and reaffirmed our commitment to reopen our Embassies once the necessary practical arrangements can be made.

"I also raised the UK's continuing concerns about Iran's approach to human rights, in particular the treatment of a number of British-Iranian dual nationals detained in Iran, including Ghoncheh Ghavami."

A Foreign Office spokesman said it is "concerned" about Ms Ghavami's detention.

He added: "We are in touch with her family and we have raised our concerns with the Iranian government and asked for more information about her welfare and the charges against her."