Diplomats said on Thursday Washington had circulated a draft resolution to the International Atomic Energy Agency (IAEA) declaring Iran in "non-compliance" with nuclear obligations.
But they said Washington realised there was little support for the resolution, as the case for declaring Iran in breach is far from clear cut.
The United States accuses Tehran of secretly developing atomic weapons, a charge Iran denies.
If the resolution had been approved by the IAEA board the Security Council could have imposed economic sanctions on Iran.
However, one diplomat said Washington would try again to report Tehran to the Council in November.
A senior Western diplomat said the United States would now support a resolution demanding Iran urgently comply with its IAEA nuclear Safeguards Agreement to help the agency "get to the bottom of Iran's nuclear programme".
"I think we need to strengthen the hand of the agency," the diplomat said.
Kamal Kharrazi (R) denies Iran is
developing nuclear weapons
Iran's foreign minister said in remarks published on Friday that he hoped the board would not be swayed by politics or US pressure.
"We hope the Americans would not pressure the agency and its board of governors to adopt a political stance," Foreign Minister Kamal Kharrazi said.
Iran has been under pressure to sign up to the so-called Additional Protocol to the Non-Proliferation Treaty (NPT) which would allow intrusive, short-notice inspections of its nuclear facilities.
Iran has said it is ready to start negotiations on signing the protocol but wants clarifications about some sovereignty issues, a caveat analysts say could lead to delays.
"By answering Iran's questions, it is possible to have the required consensus in Iran for joining the Additional Protocol," Kharrazi said.