"Last night we were a long way from foreign ministers coming. Today it has got closer," Iran's Foreign Minister Mohammad Javad Zarif said, according to the ISNA news agency.
Differences however remained.
This third meeting in Geneva since President Hassan Rouhani was elected in June is seen as the biggest hope in years to resolve the decade-old standoff over Iran's nuclear programme.
Failure might mean Iran resuming the expansion of its atomic activities, Washington and others adding to already painful sanctions, and possible Israeli military action.
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Both sides say they want a deal but getting an accord palatable to hardliners both in the United States and in the Islamic republic -- as well as Israel -- has proven a daunting task.
According to a draft proposal hammered out on November 9, the United States, Britain, China, France, Russia, and Germany -- the P5+1 -- want Iran to freeze for six months key parts of its nuclear programme.
This hoped-for "first phase" deal would build trust and ease tensions while Iran and the six powers hammer out a final accord that ends once and for all fears that Tehran will get an atomic bomb.
After yesterday's sessions Iranian diplomats were downbeat.
But today signals coming out of Tehran appeared to indicate an improvement after only an hour-long meeting between Zarif and the powers' chief negotiator Catherine Ashton.