The UN nuclear watchdog has adopted a resolution condemning Iran for keeping some of its nuclear activities secret.
The US accuses Iran of hiding evidence of a nuclear weapons programme
However, the resolution stopped short of threatening UN sanctions against Tehran which the US had pressed for.
The deal comes after a week of intense negotiations by the 35-member board of governors of the International Atomic Energy Agency (IAEA).
But Iran described the resolution as a setback and implied that it had been imposed on the body by the US.
"A resolution is being imposed, and I think I am using the
expression with true definition of the word, on the board by a single country," senior foreign
ministry official Amir Zamaninia told the meeting.
He added that the resolution had portrayed a "benign progressive situation" as a state of high alert.
But Kenneth Brill, the US envoy to the IAEA, said the resolution made it clear that the board was not yet satisfied with Iran's co-operation.
The deal follows Iran's unexpected decision to postpone UN inspections of its sites for the next month.
Western diplomats said the move was disturbing, but Tehran's ambassador to the UN in Vienna, Pirooz Hosseini, said inspections would only be delayed three weeks because of Iran's New Year celebrations which begin next week.
"This is just purely a vacation issue," he told Reuters news agency.
A diplomat close to IAEA, says the postponement is expected to last much longer than the official four-day holiday and is clearly not the reason for Tehran's sudden decision.
The US accuses Iran of systematically hiding evidence of nuclear weapons development.
Iran says its nuclear programme is for peaceful purposes only.
Canada, Australia and Ireland presented the US-backed text for discussion, while Malaysia spoke for the 13 non-aligned states on the IAEA board.
Non-aligned Movement countries have been trying to soften the tone of the toughly-worded draft to avoid alienating Tehran.
But diplomats said that while dropping most of their objections the countries had changed the wording of the resolution, in effect deferring the threat of action against Iran until the board meets again in June.
Iran's ambassador had described the original draft as an act of US bullying.
Mr Hosseini later told AFP news agency that Iran would still co-operate with the IAEA regardless of the resolution adopted.