In addition to encouraging Iran's practice of capturing and imprisoning American citizens on politically-driven charges, the deal to release Rezaian and the other USA captives will likely strengthen Syrian dictator Bashar al-Assad, Josh Rogin reported Sunday for Bloomberg View.

One of the four American prisoners released from Iran over the weekend said Tuesday that having his freedom back is "like being born again".

A deal had been negotiated between Washington and Tehran for the release of Jason Rezaian (left), but, with just hours to go, Iranian authorities held his wife, Yeganeh Salehi (center left), and mother, Mary (center right), in a separate room without telephones.

He stressed that he feels "extremely lucky" and "alive for the first time in a long time".

"I was at a point where I had just sort of accepted the fact that I was going to be spending 10 years in prison", he said.

Hekmati said the Swiss served up chocolates and veal on the flight. They were accused of exporting goods ranging from electronic components and satellite services to marine navigation and military equipment to Iran.

STAFF/REUTERS Amir Hekmati (center), flanked by U.S. Congressman Dan Kildee (l.) and brother-in-law Ramy Kurdi, speaks with media in Landstuhl, Germany, on Tuesday for the first time since his release. Amir Hekmati was detained in August 2011 on espionage charges.

Officials have said Hekmati was put in solitary confinement and subjected to sleep deprivation.

"Iran's release of the (American) prisoners was a result of government discretion, not the rule of law correcting a grotesque miscarriage of justice in Iran", says Hadi Ghaemi, who heads the International Campaign for Human Rights in Iran.

When the plane finally took off, the passengers - including Rezaian, the other released Iranian Americans, and Rezaian's wife and mother - burst into applause.

"Champagne bottles were popped", Hekmati said. It said they have used front companies to deceive foreign suppliers about the true end-users of "sensitive goods for missile proliferation". A fifth American detainee, student Matthew Trevithick, was released separately and has already returned to the United States.

A reporter asked the State Department spokesman about it in a briefing in October, saying: "I believe his title is 'Special Envoy for the Fight Against ISIL and Extremism.' So why would he - why would the secretary bring him to a meeting about the Iran nuclear deal?" according to a transcript.

Hekmati's sister, Sarah Hekmati, told reporters she was upbeat as she arrived earlier Monday at Frankfurt airport before heading toward the Landstuhl medical center.

He was then tried and sentenced to 10 years in prison for cooperating with and collaborating with the US government.

The fourth American freed was Nosratollah Khosravi-Roodsari, who did not travel on the plane that departed Tehran on Sunday.

Amir hasn't made any long-term decisions on what he'll do after he returns to the U.S., Kildee said.

The Iranian Foreign Ministry said in a statement: "Iran's missile program has not been designed for carrying nuclear weapons at all, and therefore it doesn't violate any worldwide rule". "They just came one morning and said 'pack your things'".