Britain, France and Germany have reached an agreement with the United States on a UN resolution to warn Iran over its nuclear programme.
Iran denies it is developing nuclear weapons
Washington rejected an earlier draft, insisting that Tehran should be given a tough warning over past failures to declare all its nuclear activities.
Diplomats say a compromise was agreed after five days of talks.
It is due to be discussed by governors of the International Atomic Energy Agency (IAEA) on Wednesday.
A Western diplomat in Vienna, where the IAEA is based, told the BBC that the new resolution should be acceptable to all the board's 35 members.
The members had been trying to reach agreement on how to respond to 18 years of failure by Iran to disclose key aspects of its nuclear programme.
According to a recent IAEA report, these included secretly enriching uranium and producing plutonium.
The United States accuses Iran of trying secretly to develop nuclear weapons
- an accusation denied by Tehran.
The US had insisted that the resolution should contain a threat of Security Council action against Iran.
However, Britain, Germany and France had been concerned that this might alienate Iran, which has shown increased co-operation with the IAEA in recent weeks.
The compromise text contains no threat of referral to the security council - a fact that has been welcomed by Iran.
"It is an achievement by all those parties who sought to resolve the issue, peacefully," the Iranian ambassador to the agency, Ali Akbar Salehi, told the BBC's World Today programme.
The compromise resolution is thought to include a "trigger mechanism" that refers indirectly to possible Security Council action in the future.
"Should any further serious Iranian failures come to light, the board of governors would meet immediately to consider in light of the circumstances... all options at its disposal," the Associated Press news agency quotes the resolution as saying.
The phrasing is weaker than the original demands of the United States.
However, the new draft is stronger than the text put forward by France, Germany and Britain last week.
This called on Iran to continue its commitment to open its nuclear facilities to strict IAEA scrutiny - a wording rejected by Washington.
Earlier, Iran said it would not tolerate any direct mention of Security Council action.
The Iranians say their nuclear programme is designed to meet the country's energy needs only.
Although the IAEA censures Tehran for breaching nuclear safeguards for almost two decades, it also said there was no evidence of an Iranian nuclear weapons programme.