The Iranian nuclear negotiating team's international media advisor during the Vienna talks, Seyed Mohammad Marandi, says the cornerstone of the success of the talks on the prisoner swap with the United States was the international challenges that were faced by Washington.

"The Americans' seriousness about the prisoner swap talks and the unfreezing of Iranian assets has seen an uptick over the past few months," Marandi told Al Mayadeen on Monday.

The most important thing for Iran is the freedom of its prisoners who are detained in the United States, he said. "They were wronged and unjustly detained," the diplomat stressed.

Iranian Foreign Ministry spokespersonNasser Kanaani announced earlier that the exchange will involve five prisoners from each country, IRNA reported.

This exchange saw the return of two Iranian prisoners to their home country, while two others will remain in the United States, and one individual will be reunited with their family in a third country, as per Kanaani's remarks.

'Greater steps'

"Tehran is awaiting greater steps from the United States to reach an agreement on bigger issues, such as the nuclear deal," Marandi underlined.

"The ongoing talks in US circles about the latest prisoner swap is but words to feed media consumerism. "The future will prove that Washington will be forced to retreat due to its foreign policies and internal challenges."

Talking about Iran's return to the negotiations table regarding the nuclear deal, Marandi told Al Mayadeen that Tehran hopes Washington is open to negotiations after the latest agreement they struck.

Read more: Tehran 'ready' to resume JCPOA talks based on 2022 draft: Iran FM

AFP reported on Monday that frozen assets totaling $6 billion have been transferred to Qatari banks as part of a US-Iran prisoner exchange arrangement, with an aircraft on standby in Tehran to transport out five American captives.

The news came in the wake of reports that a Qatari aircraft was currently positioned in Iran, ready to transport five detained US citizens and two of their relatives as part of a prisoner exchange, according to a source familiar with the situation who spoke to AFP.

Qatar played a key role in mediating talks between Iran and the United States that led to the prisoner exchange deal on August 10.