PRESIDENT Donald Trump had rare positive words for Iran yesterday, thanking the US foe for a “very fair” negotiation to successfully pull off a prisoner swap that saw an American released from Iranian detention amid soaring tensions.

The exchange, which took place in neutral Switzerland, involved a Princeton graduate student jailed in Iran for espionage since 2016 and an Iranian national arrested over a year ago in Chicago.

“Thank you to Iran on a very fair negotiation,” tweeted Trump, as Xiyue Wang made his way home to his family.

The US leader was expected to welcome Wang in person when he arrives in the United States, after a stop in Germany for medical evaluations.

“It was a one-on-one hostage swap,” Trump told reporters. “I think it was great to show than we can do something. It might have been a precursor as to what can be done.”

A photo tweeted by the American embassy in Bern showed Wang on a rainswept tarmac in Zurich with an official blue and white US jet in the background, hugging ambassador Edward McMullen.

The Chinese-born American was in apparent good health and in “very, very good humour”, said a senior US administration official.

Tehran had announced the release of its national, Massoud Soleimani, shortly before Trump revealed that Wang was returning home.

“Glad that Professor Massoud Soleimani and Mr Xiyue Wang will be joining their families shortly,” Iran’s Foreign Minister Mohammad Javad Zarif tweeted – along with a photograph of himself and the scientist on a plane under the words “Going home”.

The Swiss foreign ministry confirmed that the exchange – which it called a “humanitarian gesture” – took place on its territory. Both the US and Iran credited Switzerland with an intensive diplomatic effort to secure the men’s release.

The US and Iran have not had diplomatic ties since 1980, and relations have sharply worsened since Trump withdrew from an international accord giving Iran sanctions relief in return for curbs on its nuclear programme.

A doctoral candidate at Princeton, Wang was conducting research for his dissertation on late 19th- and early 20th-century Eurasian history when he was jailed in August 2016. He was serving 10 years on espionage charges. – AFP, December 8, 2019.