The move announced by the US Treasury Department on Tuesday, allows non-profit groups focused on disaster relief, wildlife conservation, human rights and similar programs to enter and work with Iran without having to apply for special permission.
It also allows Iranian and US athletes to pay for sports exchanges and matches between the two countries without a special application.
The announcement came in the run-up to a new round of talks between Tehran and the International Atomic Energy Agency (IAEA) in Vienna on September 27.
In July, the Treasury Department lifted some sanctions on a number of medical devices that can be exported to Iran without special permission.
The US, Israel, and some of their allies have repeatedly accused Iran of pursuing non-civilian objectives in its nuclear energy program, with the US and the European Union using the unfounded allegation as a pretext to impose illegal sanctions on Iran.
Tehran rejects the allegations, arguing that as a committed signatory to the nuclear Non-Proliferation Treaty (NPT) and a member of the International Atomic Energy Agency (IAEA), it has the right to use nuclear technology for peaceful purposes.
In addition, the IAEA has conducted numerous inspections of Iran's nuclear facilities but has never found any evidence showing that the Iranian nuclear program has been diverted toward military objectives.
