Iran showed a greater level of "seriousness and substance" in nuclear talks between world powers and the Islamic Republic, the White House said Wednesday.
Spokesman Jay Carney said the Iranian presentation at the talks was "useful" and showed a "level of seriousness and substance that we have not seen before," reported AFP.
During a two-day session with world powers in Geneva, Iran presented what it described as a breakthrough proposal that would include snap inspections of its atomic sites.
Iranian President Hassan Rouhani, who assumed office two months ago succeeding conservative Mahmoud Ahmadinejad, has pledged transparency on Iran's controversial nuclear program in an effort to get crippling UN sanctions lifted.
The United States and other Western powers suspect that Iran's atomic program is aimed at acquiring a nuclear weapons capability, which Tehran denies.
After presenting its proposal to break the deadlock with world powers over its nuclear program, senior Iranian negotiator Abbas Araqchi and his U.S. counterpart Wendy Sherman met one-on-one.
That meeting marked the first direct nuclear talks between the Islamic republic and Washington since 2009.
Peaceful overtures made by Iran's new President Hassan Rouhani have led to direct talks with the West, although Israel has yet to be convinced that Iran has dropped its ambitions to acquire a nuclear weapon. As recently as Monday, Iran's supreme leader, Ayatollah Ali Khameini, continued to fuel doubts as he appealed to Muslims around the world to unite against Israel.
Israel has said that anything short of a cessation of uranium enrichment would not safeguard the Middle East and the world from the reality of an Iran with a nuclear weapon.
Following a meeting late on Monday, the security cabinet issued a unanimous statement warning the international community against any "partial agreement that would fail to bring about the full dismantling of the Iranian military nuclear program... (which) could lead to the collapse of the sanctions regime."