FNA- Foreign Ministry Spokesman Bahram Qassemi rejected recent claims that Tehran has kept Nazanin Zaqhari - an Iranian-British citizen who has been convicted for security crimes - in jail until London makes its long overdue payments to Iran.

"Mrs. Zaghari, as an Iranian citizen, has been convicted by the Islamic Republic of Iran's judiciary and security bodies for different crimes and she has been tried according to the Islamic Republic of Iran's laws and is serving her sentence," Qassemi told FNA on Sunday after Zaghari's husband Richard Ratcliffe claimed Iranian officials have told him that his wife is being kept in prison for London's unsettled dues to Tehran.

He said speculations about Mrs. Zaghari's accusations and linking them to the bilateral relations between Iran and Britain are unfounded and untrue, and reiterated that Zaghari is in jail for her crimes and her case is no way related to the financial differences between Tehran and London.

Nazanin Zaghari-Ratcliffe, a 40-year-old project manager with the Thomson Reuters Foundation, was arrested in Tehran in April 2016 as she was returning to Britain.

While the British media have claimed that she was arrested after a family visit, Britain's Foreign Secretary Boris Johnson told a parliamentary committee in November 2017 that Zaghari-Ratcliffe was "simply teaching people journalism as I understand it" when she was arrested at Tehran airport.

Meantime, in November 2017, Iranian Ambassador to London Hamid Baeedinejad said that Britain is due to pay its £400mln debt to Tehran soon, dismissing any link between the payment and the case of Zaghari.

Over £400-mln ($596mln) sum will be transferred to the Central Bank of Iran “in the coming days”, Baeedinejad wrote on his Telegram channel at the time.

The Iranian diplomat further expressed regret over certain media attempts to link the debt pay-off to the case of Zaghari.

The payment “with regard to a 1974 arms deal has nothing to do with the case of Nazanin Zaghari who has been arrested in Iran over security charges or to any other issue,” Baeedinejad told reporters in November 2017.