US President Barack Obama told Reuters on Monday that Iran must agree to freeze their sensitive nuclear activity for a decade for a deal to be reached between Tehran and six world powers.
In an interview with CNN, Zarif indicated Tehran's willingness to work with negotiators on the stipulation.
"If we have an agreement, we are prepared to accept certain limitations for a certain period of time but I'm not prepared to negotiate on the air," Zarif said.
He was quoted by the Iranian media on Tuesday as saying that the demand for the freeze was "unacceptable."
