Hossein Fereydoun, the brother Iran’s President Hassan Rouhani, has been arrested on unspecified financial crimes charges, according to media reports. 

Citing Iranian news agencies, The Guardian reports that Hossein Fereydoun, a top presidential aide who played a senior role in more than two years of high-level negotiations between Iran and the west over Tehran’s nuclear program, was taken to prison after failing to secure bail on Saturday.   

Gholam-Hossein Mohseni-Ejei, the spokesman for the Iranian judiciary, confirmed the news on Sunday during a weekly press briefing in Tehran.

“A bail order was issued for him yesterday and because he did not secure the bail, he was taken to jail. If he does so, he will be released on bail,” he said, according to quotes carried by the semi-official Iranian Students’ News Agency.

Iran’s state-run English-language Press TV reports that Mohseni-Ejei noted that some other people had been already arrested in that regard.

He added that if Fereydoun could post the bail asked by court, he would go free, because he was not in temporary detention.

When a reporter asked about Fereydoun's charges, the Judiciary spokesman said they were related to financial issues, but had nothing to do with bank arrears, according to Press TV.

Rouhani’s supporters have reportedly seen his brother’s arrest as part of efforts to undermine him during his second term in office.

Fereydoun’s detention comes a few weeks ahead of Rouhani’s swearing-in ceremony following his landslide victory in May’s presidential election, complicating an already tense atmosphere between him and hardliners. 

Fereydoun came in high-level contact with American officials during the nuclear talks.  

Prior to Rouhani’s first victory in 2013, Fereydoun was a veteran diplomat and had served as Iran’s ambassador to Malaysia for eight years and later as a senior diplomat at Iran’s delegation to the UN.

The difference between the two brothers’ surnames is due to the fact that the president changed his family name Fereydoun to Rouhani as a security measure to avoid the attention of the Savak secret police when preaching against the shah before the 1979 Iranian revolution.  Rouhani means cleric in Farsi.