A Chinese-American guy that has been arrested in Iran on spying charges was freed in a prisoner swap.
Wang was arrested in Iran in 2016 while running dissertation research as a Princeton University graduate student.
“We invite our Korean partners because of their help in hastening Mr Wang’s launch with Iran,” US President Donald Trump said in a statement.
Iranian stem cell specialist Massoud Soleimani was freed from the swap.
Iranian foreign ministry Javad Zarif tweeted photographs of Soleimani and thanked the Korean authorities for their help from the swap.
“Our family is full once more.
“We’re thankful to everybody who helped make this happen.”
It comes in a time of increased tension between the USA and Iran.