Iran’s President Hassan Rouhani proposes a prisoner exchange with the United States. Washington Post correspondent Jason Rezaian is among the Americans jailed in Iran who might be released.

In an interview with CNN's Christiane Amanpour on Sunday, Rouhani said Iran would be inclined to release American prisoners if the U.S. releases Iranians it is holding.

"If the Americans take the appropriate steps and set them free, certainly the right environment will be open and the right circumstances will be created for us to do everything within our power and our purview to bring about the swiftest freedom for the Americans held in Iran as well," Rouhani said.

Rouhani is currently in New York to address the 70th UN general assembly.

Three Americans are known to be held in Iran: Washington Post journalist Jason Rezaian, former U.S. Marine Amir Hekmati and Christian pastor Saeed Abedini. A fourth American, Robert Levinson, former FBI agent and contractor for the CIA, went missing after visiting the country in 2007, but Iranian officials denies having any knowledge of his whereabouts.

The Washington Post reporter Jason Rezaian, a dual Iranian-American citizen, has been imprisoned in Iran since July 22, 2014. Rezaian, who has declared his innocence, is charged with a number of offences, including espionage, and could face up to 20 years in prison.

19 Iranian citizens are in prison in the U.S. on charges related to sanctions against Iran’s nuclear program. As a result of the historic nuclear deal between Iran and the P5+1 countries, which was signed in Vienna on July 14, Rouhani said there is no reason for the U.S. to hold these prisoners.

"There are a number of Iranians in the United States who are imprisoned, who went to prison as a result of activities related to the nuclear industry in Iran. Once these sanctions have been lifted, why keep those folks in American prisons?," Rouhani asked. "So they must be freed."

Following the interview, Secretary of State John Kerry, was according to CNN asked whether he would support such an exchange:

"I have yet to hear directly from the Iranians on anything direct," Kerry responded. "We've had some conversations but ... we'll wait and see where we are."