The meeting would be the most significant contact between Iran and the United States since diplomatic ties were severed in April 1980 following the 1979 Iranian revolution that overthrew the late Shah Reza Palavi and led to the 444-day U.S. hostage crisis.
Hopes for a turnaround have been fueled by a series of recent statements and positive gestures by Rouhani and other Iranian officials, who apparently have received the blessings of Irans supreme leader, Ayatollah Ali Khamenei, to seek a settlement to the nuclear dispute.
Some U.S. officials and analysts attribute the change to the damage to oil-rich Irans petroleum-fueled economy by international sanctions imposed for its defiance of U.N. Security Council resolutions ordering it to stop enriching uranium, the process that produces fuel for power plants and for nuclear weapons.
The United States and the European Union have imposed their own harsh measures to cut Iran off from the international banking system, and ending international investment in the Islamic republic.
But Iranian officials and other analysts point to Rouhanis substantial election victory over a number of conservative candidates after a campaign in which he pledged to end Irans international isolation and find a negotiated resolution to the nuclear crisis.
Talks between the so-called P5-Plus-1 the United States, Russia, France, Britain, Germany and China with Iran on its uranium enrichment program have been stalled since the last round was held in April.
The United States and other powers suspect that Iran is using its program which it kept hidden for 18 years from inspectors of the U.N. International Atomic Energy Agency to develop the ability to quickly assemble nuclear warheads if it ever decides to do so. Iran counters that it is enriching uranium for fuel for power generation.