Iranian Supreme Leader Ayatollah Ali Khamenei has reportedly sent a secret letter to US President Barack Obama calling for better relations between the two countries.
Responding to Obama's overture that the US would step up cooperation with Iran in the fight against the Islamic State (Isis) if an Iranian nuclear deal is reached, Khamenei is thought to have replied cautiously.
The Wall Street Journal, citing an Iranian diplomat who is aware of the matter, said Khamenei's response was "respectful" but non-committal.
Khamenei wields the highest authority in Iran and has the last word on political matters.
The WSJ also revealed that the top Iranian cleric sent another letter to Obama in 2009 detailing the abuse of Iranians at the hands of US forces in the last six decades.
Both Iranian and US officials are tight-lipped over the direct communications between the two leaders. A White House official was quoted as confirming the existence of the first letter but he declined to comment on specifics.
The latest revelations have surfaced when Iran is holding talks with the P5+1 powers comprising the US, Britain, Russia, China, France and Germany over Iran's nuclear activities.
The Western powers have long been accusing Iran of having ambitions to make nuclear weapons through a covert programme. Iran strongly denies the accusation arguing its nuclear programme is only for peaceful purposes.