Iran's foreign ministry said Monday it has sent the US a list of names it is demanding in a proposed prisoner swap.
Foreign Minister Mohammad Javad Zarif said he hoped to hear soon "good news" about the release of Iranian scientist Masoud Soleimani, although Tehran did not detail the names it relayed.
US federal authorities arrested Soleimani last year on charges that he had violated trade sanctions by trying to have biological material brought to Iran, the Associated Press (AP) reported.
Zarif said he raised the issue last month in his visit to New York to attend the UN General Assembly, according to the semi-official Fars news agency.
Ministry spokesman Abbas Mousavi said his country has relayed which Iranians should be included in the suggested swap with US and other Western nations.
Meanwhile, Iran holds several US nationals and did not detail whom it would consider freeing.
"We have handed over a list of names (to the United States) who must be freed," Mousavi said, in a briefing with reporters.
"We hope that these efforts, if paired with good will, would pay off soon and we would see freedom of Dr. Soleimani and other Iranians from the Americans' captivity."
Tensions between Iran and the US have steadily escalated since President Donald Trump pulled the United States out of the 2015 nuclear deal last May and re-imposed sanctions on Iran.
According to AP, the US blames Iran for a series of mysterious oil tanker attacks this year. Iran denies the accusations and has warned any retaliatory attack targeting it will result in an "all-out war," as it has begun enriching uranium beyond the terms of its 2015 nuclear deal.