Washington accused of paying ransom as five detainees from each side are released.
A British environmentalist held hostage in Iran is among five prisoners who have been released in a $6bn swap deal with the United States.Morad Tahbaz, who holds British, American and Iranian citizenship, was among the prisoners flown out of Iran on Monday afternoon, following weeks of negotiation between Washington and Tehran.
London-born Mr Tahbaz, 67, was arrested in 2018 and sentenced to 10 years in prison on charges of "assembly and collusion against Iran's national security" while working as a climate activist.
His imprisonment has become a major diplomatic dispute between Iran and the UK, and has featured in negotiations between the governments over the detention of Nazanin Zaghari-Ratcliffe.
Roxanne Tahbaz, his daughter, has campaigned in Britain for ministers to do more to secure his release, including at protests outside the Foreign Office.
But Mr Tahbaz was left in Iran when Ms Zaghari-Ratcliffe and another British-Iranian dual national, Anoosheh Ashoori, were released in a deal negotiated by Liz Truss, when she was Foreign Secretary.
themes: Washington

First Thing: US and Iran expected to complete $6bn prisoner swap deal
Conservationist Morad Tahbaz among prisoners to be swapped in deal involving unfreezing of Iranian oil money. Plus, has the Chinese economy reached its peak?
Good morning.The US and Iran are expected to pull off a controversial prisoner swap today involving the unfreezing by the Biden administration of $6bn (?4.8bn) of Iranian oil money held in South Korea since 2018.

Iran-US prisoner swap: How Democrats and Republicans reacted to the deal
Washington, DC - Republicans have denounced Monday's prisoner swap between the United States and Iran, saying that the deal provides an incentive for Tehran to detain more Americans in future.
Officials in the administration of US President Joe Biden, however, hailed the release of the five US citizens from Iranian custody, adding that they would soon be reunited with their families.
Five Iranian prisoners in the US were likewise returned to their home country.
The Qatar-brokered agreement also saw the unfreezing of $6bn in Iranian funds formerly held in South Korea. Prior to Monday's deal, the funds could not be transferred due to US sanctions against Iran.
Here's how Republicans and Democrats reacted to the agreement.

Five Americans land in Doha after release in US-Iran prisoner swap
A plane carrying five American prisoners released by Iran as part of a high-profile prisoner exchange has landed in the Qatari capital Doha, before the former detainees are expected to then fly on to the United States.
The former detainees walked off the plane on Monday onto the tarmac at Doha International Airport after arriving from Tehran. They were greeted by both US and Qatari officials.
Al Jazeera's Imran Khan, reporting from the airport, said that the former prisoners were not expected to spend long in Qatar, and would soon be on their way home to the US.
"There's a visible sense of actual relief," Khan said. "Its all smiles now."
Two of the five Iranians imprisoned by the US have already arrived in the Gulf state, before they transit on to Iran. The three other released Iranians have decided against returning to Iran, with two staying in the US, and one going on to a third country.
The agreement between the US and Iran has also seen $6bn in Iranian assets held in South Korea unfrozen, triggering the prisoner exchange.
US President Joe Biden welcomed the return of the five citizens and thanked allies for helping secure their release.
"Siamak Namazi, Morad Tahbaz, Emad Sharghi, and two citizens who wish to remain private will soon be reunited with their loved ones - after
enduring years of agony, uncertainty, and suffering," Biden said in a statement released by the White House.
"I am grateful to our partners at home and abroad for their tireless efforts to help us achieve this outcome, including the governments of
Qatar, Oman, Switzerland, and South Korea."
Biden also reminded US citizens about the risk of travelling to Iran and said Washington could not guarantee their freedom should they be detained.
"American passport holders should not travel there," he said.
The White House has come under criticism from Republicans and some Democrats for striking the prisoner exchange deal with Tehran, saying that it could lead to further detentions.
Al Jazeera's Kimberly Halkett says the Biden administration has repeatedly said freeing US citizens imprisoned abroad is a top priority of his presidency.
"Anyone who has a family member in detention would want to see their family member brought home, and that is his top priority. That was the opportunity that was in front of him and so he seized it," Halkett added.
This is a developing story, more to follow.

Who are the five American prisoners freed in the Iran-US prisoner swap?
Five US citizens have been flown out of Iran as part of a widely anticipated prisoner swap deal between Washington and Tehran, a United States official confirmed.
A senior official in US President Joe Biden's administration told reporters on Monday that five freed Americans and two of their US family members were en route to the Qatari capital, Doha.
The White House has named three of the prisoners, who were released to house arrest in advance of the swap, as Siamak Namazi, Emad Sharghi and Morad Tahbaz.
The families of the two others have withheld their identities, but they are said to be a scientist and a businessman. Western media outlets also have reported that one is a woman.
Here's what we know about the Americans being released as part of the deal:

Who Are the US Detainees Released in Prisoner Swap With Iran?
Here is a look at the detainees released Monday as part of a prisoner swap between the United States and Iran.
Siamak Namazi
Siamak Namazi, 51, was the longest held Iranian American detainee. He was arrested in 2015 and sentenced the following year to 10 years in Tehran's Evin Prison on charges of espionage. Months later, his father was arrested when he visited Iran to check on his son. The elder Namazi was later placed on house arrest and permitted to leave Iran in 2022 due to medical reasons. Namazi is an energy executive who promoted closer ties between the west and Iran.
Emad Sharghi
Emad Sharghi, 59, is an Iranian American venture capitalist who moved to Iran with his wife in 2017. He was detained the following year, but his family says he was released after going through eight months of interrogations. Authorities rearrested Sharghi while he was trying to leave the country while on bail. He was charged with espionage and sentenced to 10 years in prison.
Morad Tahbaz
Morad Tahbaz, 67, was also sentenced to 10 years of prison. He is an Iranian American conservationist who also holds British citizenship. In 2018, he was arrested during an Iranian crackdown on environmental activists. Tahbaz had reportedly remained in prison despite an agreement between the United Kingdom and Iran that he be released from prison on furlough.
Two unnamed detainees
Two additional prisoners were released Monday. However, the U.S. government has not released their names at the request of their families.
The Iranians
Five Iranians charged or convicted of nonviolent crimes in the United States received clemency under the deal:
Kaveh Lotfolah Afrasiabi
Mehrdad Ansari
Amin Hasanzadeh
Reza Sarhangpour Kafrani
Kambiz Attar Kashani
Some information for this story came from the Associated Press and Reuters.

Iran ready to implement prisoner swap deal with US, official says
Iran's foreign minister has said his country is ready to implement a Qatar-mediated deal with the United States, under which Washington and Tehran each would free five prisoners and $6bn in Iranian assets held in South Korea would be released.
The broad outlines of the US-Iran deal under which US citizens detained by Iran would be allowed to leave in exchange for the transfer of the funds to banks in Qatar and the release of five Iranians held in the United States were made public on August 10.
Foreign Minister Hossein Amirabdollahian, in a telephone conversation with his Qatari counterpart on Thursday, praised Doha's constructive role during months of negotiations that resulted in clinching the pact, Iranian state media reported.
Qatar's prime minister and foreign minister, Sheikh Mohammed Bin Abdulrahman Al Thani, said the process of wiring the Islamic Republic's unfrozen funds to Qatari banks will be completed as early as next week, Iranian media reported.
Washington has waived sanctions to allow the transfer of $6bn in Iranian funds from South Korea to Qatar, which will monitor how Iran's clerical rulers will spend the funds to purchase humanitarian goods.

US-Iran prisoner swap 'important first step' but tensions remain: Analysts
Washington, DC - The prisoner swap between the United States and Iran is a step towards de-escalating tensions between the two countries, experts say, but it does not point to an imminent thaw in frosty relations.
Alex Vatanka, director of the Iran programme at the Middle East Institute think tank in Washington, DC, called the prisoner exchange a "transactional deal".
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"Everybody is basically reconciling themselves with the fact that the best they can do for now is to take small steps toward preventing a crisis," Vatanka told Al Jazeera.
"So that's all it is. There is no big vision being articulated by anybody that could tell us that something in terms of a breakthrough is in the pipeline. There is no sign of that."
Five American citizens previously detained in Iran were flown out of the country on Monday as part of the agreement, which was facilitated by Qatar and other countries.
They landed in the Qatari capital, Doha, on Monday afternoon and were expected to be "soon be reunited with their loved ones-after enduring years of agony, uncertainty, and suffering", US President Joe Biden said in a statement.