°®Âþµº

The UK government should investigate six-year detention of dual national as "an act of hostage-taking" and try to prosecute Iranian officials, said on Wednesday.

The rights group has compiled a detailed analysis of the case, which it says includes "compelling evidence that Iran's detention of Nazanin Zaghari-Ratcliffe amounted to an act of hostage-taking".

Zaghari-Ratcliffe, 43, who was first detained in Iran in 2016, returned to Britain in March along with fellow dual national Anoosheh Ashoori after the UK agreed to pay a longstanding debt to Tehran.

"The Iranian authorities deliberately and shamelessly deprived Nazanin Zaghari-Ratcliffe of her freedom," Diana Eltahawy, deputy director for the Middle East and North Africa at Amnesty, said in a statement.

"They used spurious national security charges and sham judicial proceedings against her with the aim of exerting pressure on the UK government to settle its debts."

The NGO last month submitted its evidence to the UK parliament's Foreign Affairs Committee, which has launched its own inquiry into state-level hostage situations.

Amnesty said there was an urgent need for the international community to step up efforts to prevent and prosecute hostage-taking amid growing evidence that Iranian authorities are holding others unjustly.

It highlighted at least seven cases of dual nationals currently held in Iran, including Swedish-Iranian Ahmadreza Djalali, Austrian-Iranians Kamran Ghaderi and Massud Mossaheb and German-Iranians Nahid Taghavi and Jamshid Sharmahd.

Two other British-Iranians, Mehran Raoof, and Morad TahbazÌý– who is also a US nationalÌý– are also still detained by Tehran.

Brit-Iranian Anoosheh Ashoori grabbed headlines after he, along with Nazanin Zaghari-Ratcliffe, was freed from Iranian jail. He and his wife Sherry Izadi now say they will not stop speaking up about other dual nationals left behind ⬇

�

— °®Âþµº (@The_NewArab)

"The prevailing climate of impunity in Iran has emboldened the authorities to continue using dual and foreign nationals as political bargaining chips without any fear of consequences," Eltahawy added.

"The hostage-taking of Nazanin Zaghari-Ratcliffe must not go unpunished."

Amnesty urged the British government to review the evidence in her case and request the extradition of Iranian officials "in order to prosecute them in fair trials".

It noted both and the UK are parties to the International Convention Against the Taking of Hostages, which criminalises hostage-taking by state and non-state actors and obligates them to take action to prevent and punish such acts.