Western diplomats say Iran has agreed to let the International Atomic Energy Agency have greater overview of a uranium-enriching site in Iran.
The officials, speaking on condition of anonymity, made the announcement to news agencies Friday.
There was no immediate confirmation from Iran.
On Thursday, U.S. Vice President Joe Biden said he expected the United Nations will impose a new round of sanctions against Iran by the beginning of next month over its nuclear program.
The United States and its allies believe Iran is secretly trying to develop nuclear weapons, but Tehran has insisted its nuclear program is for peaceful, civilian purposes.
Some information for this report was provided by AP and Reuters.