The move announced by the US Treasury Department on Tuesday means non-profit groups focused on disaster relief, wildlife conservation, human rights and similar programs will no longer have to apply for special permission to enter Iran and conduct business there.

It also allows Iranian and US athletes to pay for sports exchanges and matches between the two countries without a special application, which can help encourage exchanges, analysts say.

The United States and its European allies have ramped up tough measures against Iran in recent years to slow development of the Islamic Republic's nuclear energy  program, blacklisting a wide range of Iranian companies and government officials and curbing Iran's oil exports.

The United States believes Iran is enriching uranium to levels that could be used in nuclear weapons, but Tehran says its program is for peaceful purposes.

Iran's election of a moderate, Hassan Rouhani, as president this summer has raised some hopes for a resolution of the long-running dispute over Iran's nuclear program.

The United States and Iran have had no diplomatic relations since 1980.

NIAC, a non-profit grassroots group, has long urged the US government to ease restrictions on Iran that hurt ordinary citizens.

The US government has claimed it always tries to sanction Iran without unduly harming ordinary Iranians, granting licenses, for example, to US companies that want to export pharmaceuticals, medical devices, food and other humanitarian goods to the country.

US diplomats found rare common ground with the Islamic Republic earlier this year over keeping wrestling as a sport in the Olympics, and Iranian wrestlers had a friendly match with their US counterparts in May at New York's Madison Square Garden.

BA/BA