An interim nuclear deal between Iran and six world powers and Iran will start on 20th January, the EU's foreign policy chief Catherine Ashton said.
Ashton represents the six nations - the United States, Russia, China, France, Britain and Germany - in diplomatic contacts with Iran related to the nuclear standoff.
She said the sides would now ask the United Nations' nuclear watchdog to verify the deal's implementation.
"We will ask the IAEA to undertake the necessary nuclear-related monitoring and verification activities," she said.
Under the agreement, Iran has promised to curb its most sensitive nuclear activities in return for some relief from Western economic sanctions.
More top news
Two police officers face a gross misconduct hearing after stopping at McDonald's before attending an emergency call for a suicidal woman.
International Development Secretary, Priti Patel, urged the rest of the world to 'act now' to help millions of people at risk of starvation.
Nail-biting footage of two thrill seekers climbing to the top of One Canada Square in London's Canary Wharf has emerged online.