US Special Representative for Iran Brian Hook said that a diplomatic door was still open for a wider negotiation with Tehran
US President Donald Trump "has had the door open to diplomacy for many years", Hook said on Friday, a day after Iran freed US Navy veteran Michael White after nearly two years.
"We would like to see the (Iranian) regime meet our diplomacy with diplomacy," he was quoted as saying by the Xinhua news agency.
Hook said that US-Iranian contacts have so far been limited to mutual release of prisoners, and not concerned issues like Iran's nuclear program.
However, he reiterated that the US will stick to its policy of harsh economic sanctions on Iran, designed to force the Middle East country back to the so-called negotiating table over the Iranian nuclear program.
The release of White came a day after Sirous Asgari, an Iranian scientist detained by the US government, had returned to Iran.
US and Iranian officials however, have insisted that it was not a prisoner exchange and two cases were not linked.
Relations between the United States and Iran have become increasingly hostile since the Trump administration's unilateral exit from the Iran nuclear deal in 2018.
Washington has been mounting pressure on Tehran through a series of sanctions.
Iran has maintained a tough stance and scaled back its nuclear commitments in response.
( With inputs from IANS )