Iran's foreign minister says there are serious charges against jailed Washington Post reporter Jason Rezaian but that he is seeking to resolve the case from a "humanitarian perspective."

Mohammad Javad Zarif provided no further details during a press conference Saturday on how he could pursue the case. Rezaian, who has been jailed for over a year on charges of espionage, was recently convicted by a Revolutionary Court. Iranian officials have not provided details on the verdict or sentence.

Iranian President Hassan Rouhani has raised the idea of freeing U.S. prisoners in Iran in exchange for Iranians held in U.S. jails, but Iran's judiciary has rejected the idea.

U.S. officials, the Washington Post and press freedom groups have protested the jailing and trial of Rezaian, a duel U.S.-Iranian citizen.