The US Secretary of State John Kerry and the Iranian Foreign Minister Javad Zarif met in New York to discuss the nuclear deal, according to the State Department.
The statement said Kerry and Zarif met on the sidelines of the UN General Assembly meeting.
Kerry and Zarif also discussed the crisis in Syria and Russian air strikes against rebels fighting the Syrian government, an Iranian official said.
The UK and Iran can work together to defeat so-called Islamic State militants, Foreign Secretary Philip Hammond has said.Read the full story ›
Foreign Secretary Philip Hammond has re-opened Britain's embassy in Tehran, marking a major step after the thawing of relations.Read the full story ›
Foreign secretary Philip Hammond has arrived in Tehran to reopen Britain's embassy, marking an "historic moment" after a thawing of relations between the UK and Iran.
Mr Hammond's visits comes nearly four years after protesters ransacked the British ambassadorial residence in the Iranian capital.
Britain's embassy in Iran will reopen today, in a sign of easing relations between the west and Tehran.
The move comes four years after the building was stormed by violent protesters, leading to it being shut down.
Philip Hammond has flown to Tehran for a ceremony marking the move, in what is the first visit by a British foreign secretary since 2003.
It follows the election of Hassan Rouhani, a more moderate president under whom relations with the west have improved significantly.
This culminated with Iran signing a deal with western powers agreeing to curb its nuclear ambitions in exchange for a lifting of tough sanctions.
Announcing the move, Hammond said the move "does not mean we agree on everything" but added "the role of embasses is to build co-operation where we agree and reduce our differences when we don't".
Iran will simultaneously reopen its embassy in London, as part of a move which it is hoped can aid both countries' efforts to tackle challenges including Islamic State.
Four years after it was attacked by demonstrators, the British Embassy in Tehran is to be reopened.Read the full story ›
Supreme Leader Ayatollah Ali Khamenei said has said that Iranian opposition to the "arrogant" United States will not change despite a nuclear deal with world powers,
He added that Tehran remains sharply at odds with US policy in the Middle East.
Khamenei made the comments in an address marking the end of the Muslim holy month of Ramadan.
He said politicians should examine the agreement to ensure national interests were preserved, as Iran would not allow the disruption of its revolutionary principles or defensive abilities. American leaders sought Iran's "surrender", he said. Iran would not welcome war but if there were one, the United States would be humiliated.
Philip Hammond and Benjamin Netanyahu have had a testy on-camera exchange exposing tensions over the Iran nuclear deal.Read the full story ›
Iran's Supreme Leader has given a cautious welcome to the country's historic nuclear deal, but warned the text should be "carefully scrutinised" and claiming some of the other nations involved are "not trustworthy".
In a letter - his first public statement on the agreement - he thanked President Hassan Rouhani for the "significant step", but warned: "The text of the deal should be carefully scrutinised and the legal procedures should be taken so when the deal is ratified the other side cannot breach it."
Leader replying president’s letter on nuclear issue: You are well aware that some of the 6 states in #IranTalks are not trustworthy at all.
Under the deal, sanctions will be lifted on Iran in exchange for an agreement of long-term curbs on its nuclear programme.
Khamenei is the ultimate authority on all matters of state, but was not directly involved the negotiations.
The P+1 nations that agreed the deal with Iran are China, France, Russia, the United Kingdom and the United States.