TEHRAN - Iranian Deputy Foreign Minister Seyed Abbas Araqchi has responded to UK demands that Iran release a British national, describing the demands as blackmail. 

Araqchi said on Twitter that the UK seeks to blackmail Iran by refusing to release Iranian funds illegally frozen in UK bank accounts. 

“UK tries to blackmail Iran by taking our OWN money- illegally kept for more than 40 years- hostage in exchange for prisoners. This is never going to work. We still have a deal. Time for UK to do right thing and stop letting US to sabotage humanitarian exchange,” the Iranian diplomat tweeted.

The tweet came in response to another tweet by UK Prime Minister Boris Johnson in which he called on Iran to release a British prisoner called Anoosheh Ashoori. The premier claimed that Ashoori's detention is “wrongful.”

“Anoosheh and the other British nationals unjustly imprisoned in Iran must be able to return to their families in the UK,” Johnson said.

Earlier, UK Foreign Secretary Dominic Rabb also called on Iran to release Ashoori, which also elicited a response from Araqchi.

“On the 4th anniversary of Anoosheh Ashoori’s detention, I call on Iran in the strongest possible terms to free Anoosheh, and all our dual nationals arbitrarily detained, so they can be reunited with their families. Their ongoing detention is totally unjustified,” Rabb claimed.

In response, Araqchi tweeted, “Sec @dominicraab, you know better than anybody else that deal for release of 10 prisoners-incl Anoosheh Ashoori-was concluded weeks ago but your friends in DC froze it. Ashoori and 9 more are taken hostage by U.S. for political goals. Hope you'll explain this to your own people.”

In mid-July, Iran had insisted that it has reached a deal with the United States and the United Kingdom on a prisoner swap, underlining that it was ready to proceed with the deal as soon as the other sides fulfill their part.

Iranian Foreign Ministry spokesman Saeed Khatibzadeh confirmed at the time that a swap has been agreed with Washington and London a day after the U.S. denied the swap. “Iran is ready to proceed TODAY,” Khatibzadeh said on Twitter.

Khatibzadeh was responding to a U.S. response to an earlier tweet by Araqchi saying that the U.S. and the UK were linking the swap to nuclear talks currently underway in Vienna over the 2015 Iran nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA).

Araqchi had said ten prisoners on all sides stand ready to be swapped but the U.S. and the UK did not fulfill their part of the deal. 

“We're in a transition period as a democratic transfer of power is underway in our capital. Vienna talks must thus obviously await our new administration. This is what every democracy demands,” the deputy foreign minister said. 

He added, “US & UK need to understand this and stop linking a humanitarian exchange—ready to be implemented—with the JCPOA. Keeping such an exchange hostage to political aims achieves neither. TEN PRISONERS on all sides may be released TOMORROW if US&UK fulfill their part of deal.”

The U.S. rushed to deny that already a swap deal had been agreed with Iran, accusing it of an “outrageous” effort to deflect blame for the impasse in the Iran nuclear deal talks. “These comments are an outrageous effort to deflect blame for the current impasse,” U.S. State Department spokesman Ned Price said, 

“We stand ready to return to Vienna to complete work on a mutual return to the JCPOA once Iran has made the necessary decisions,” Price added.

The spokesman also said “there is no agreed deal yet” on the swap.

“We had been engaged in indirect talks on the detainees in the context of the Vienna process, and the delay in restarting that process is not helping,” Price noted. “While it would be more effective to make progress if we were meeting in Vienna, we are also prepared to continue with talks on detainees during this period.”

Khatibzadeh lashed out at the U.S., reiterating that a deal on the prisoners had been agreed with Washington. “‘Outrageous’=the U.S. denying simple fact that ‘there IS an agreed deal on the matter of the detainees.’ Even on how to announce it,” he said.

The Iranian Foreign Ministry spokesman added, “Humanitarian swap was agreed with US & UK in Vienna-separate from JCPOA- on release of 10 prisoners on all sides. Iran is ready to proceed TODAY.”