An Iranian proposal given to major powers this week is "not really responsive" to US concerns about Iran's nuclear program, the US State Department said on Thursday.
"It is not really responsive to our greatest concern, which is obviously Iran's nuclear program," State Department spokesman P.J. Crowley told reporters.
The Iranian proposals were submitted to the powers involved in diplomatic efforts to resolve the standoff over Iran's nuclear work -- the United States, France, Britain, Russia, China and Germany.
"In the package yesterday, Iran reiterated its view that as far as it is concerned, its nuclear file is closed," Crowley said.
The spokesman said that senior diplomats from the so-called P5+1, the five permanent members of the UN Security Council and Germany, would hold a conference call on Friday to discuss the Iranian proposal.
"As we consult with our P5+1 colleagues, we will be looking to see how ... ready Iran is to actually engage and we will be testing that willingness to engage in the next few weeks," Crowley added.
However, Russian Foreign Minister Sergei Lavrov said on Thursday that the package of proposals from Iran contained something to work with and ruled out oil sanctions against the Islamic Republic.
"Based on a brief review of the Iranian papers my impression is there is something there to use," Lavrov told academics and reporters from the Valdai discussion group in Moscow.
"The most important thing is Iran is ready for a comprehensive discussion of the situation, what positive role it can play in Iraq, Afghanistan and the region," he said.
Lavrov said that the United Nations Security Council would not support oil sanctions against Iran, the world's fifth-largest crude exporter.
'If you fail in one shot, it is a catastrophe'
He said that world powers had agreed to use sanctions only as a way to get Iran to cooperate with the International Atomic Energy Agency.
"Some of the sanctions under discussion, including oil and oil products, are not a mechanism to force Iran to cooperate -- they are a step to a full blown blockade and I do not think they would be supported at the UN Security Council," he said.
Earlier Thursday, the head of the French military said that military intervention is no longer a viable option to prevent Iran from obtaining a nuclear capability.
French chief-of-staff Gen. Jean-Louis Georgelin told an audience in Washington that he believes a military operation would be too risky.
Georgelin was answering a question after a speech in Washington on NATO and stressed that the comment was his opinion.
Georgelin said it would be difficult to plan an operation in Iran "because we are not sure in one shot to be able to solve a problem." He added: "if you fail in one shot, it is a catastrophe."
Iran says its nuclear program is aimed at producing electricity and has repeatedly rejected demands to halt enrichment, which can have both civilian and military purposes.
US President Barack Obama has indicated Iran will face much harsher sanctions, possibly targeting its lifeblood oil sector, if it does not accept good-faith negotiations by the end of September.