Iran's foreign minister says the payment of $530 million by Britain to free two detained dual citizens from Iran is not related to their release.

Foreign Minister Hossein Amir-Abdollahian said in a diplomatic reception on Wednesday in Tehran that Iran received the payment from the United Kingdom “a few days earlier” and the release of Nazanin Zaghari Ratcliffe and Anoosheh “was a coincidence.”

Iran’s government controlled media has been highlighting the receipt of the money for freeing “spies”.

The two were freed on Wednesday and headed back to Britain after long negotiations, according to Amir-Abdollahian. Both sides acknowledged that a 400-million-pound historic debt owed by the UK to Iran from mid-1970s was paid.

“I announce clearly that there is link between the release of the money and the individuals who had been arrested and tried on spying and security charges and their guilt was proven,” Iran foreign minister said.

There were numerous media reports, including in Iran's state-controlled media in the past six years about the link between Zaghari-Ratcliffe’s detention and the issue of the British debt to Iran.

In the past 43 years, the Islamic Republic has taken hostage or detained many foreigners and dual national who were exchanged for money or release of Iranians imprisoned in the West for illegal activities.

International human rights organizations say that the practice amounts to hostage taking to gain leverage against other countries.