Pakistan's powerful army chief arrived in Tehran on Friday, with Islamabad mediating as the Islamic republic examines a new US proposal to end the Middle East war.
Iran's foreign ministry spokesman Esmaeil Baqaei, however, said the visit did not necessarily mean "we have reached a turning point or a decisive situation".
The disagreements between Iran and the United States were "deep and extensive", he added in quotes carried by Iran's ISNA news agency.