There was no breakthrough at the two days of talks in Geneva, but most participants welcomed the positive atmosphere of the negotiations, the first since April.
Iran showed more flexibility during the talks, seen as a test for the seriousness of a policy change advocated by President Hassan Rouhani.
Rouhani, a reputed moderate who took office in August, has said he wants to swiftly resolve the long-decade nuclear standoff with the so-called P5+1 group -- Britain, China, France, Russia and the United States, plus Germany.
So far, Rouhani has enjoyed the qualified support of Iran's supreme leader, Ayatollah Ali Khamenei, who has the final say on all state matters including foreign policy and the nuclear issue.
But foreign analysts question the extent of Rouhani's flexibilty in the face of regime hardliners who are against any concession.
"Nuclear impasse broken in Geneva," read the front-page headline of the government-run Iran daily, hailing the outcome of the negotiations.
"At the negotiating table we discussed in detail all the steps we should take. We also drew our red lines," Iran's chief negotiator Abbas Araqchi said, quoted by the daily.
"We also proposed solutions for the West's concerns... if shipping out the enriched uranium is a red line for us, we proposed another way to tackle this concern," he said.
Major powers are particularly concerned about Iran's uranium enrichment which they suspect has military objectives.
Tehran vehemently denies this, saying that under the Nuclear Non-Proliferation Treaty (NPT), which Tehran has signed up to, it maintains the right to have peaceful nuclear technology.
In an attempt to force Iran to reel in its disputed nuclear activities, the United Nations has imposed several rounds of sanctions against Tehran.
The United States and European Union have slapped the Islamic republic with additional punitive measures against its oil and banking sectors.
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The sanctions slashed Iran's oil revenues by more than half, seen the rial plunge against other currencies and caused inflation to surge by more than 40 percent, according to official data.
The reformist Etemad newspaper lauded the "new spring of negotiations," in a column by former diplomat Ali Khoram.
Rouhani, he wrote, wanted to "open a new chapter in negotiations, while emphasising the country's fundamental rights under (the NPT), including uranium enrichment.
"It is ready to undertake extensive cooperation to build trust".
"But the West should not overestimate the impact of sanctions, assume it has the upper hand and that it is (only) up to Iran to show flexibility," added Khoram.
Some observers said Tehran should defend its legal rights .
"As a member of NPT, Iran's enrichment rights should be emphasised and approved by the West," said Gholamali Khoshrou, a member of Iran's negotiating team led by Rouhani in 2003 and 2005.
"If there is mistrust on the other side about Iran's goodwill, we should tackle these concerns through legitimate mechanisms and legal tools."
The official IRNA news agency said "another victory in Rouhani's record, Iran's glowing nuclear diplomacy in Geneva," noting "optimism" among the diplomats involved in the negotiations.
According to IRNA, this "opportunity" created by the election of Rouhani, could pave the way for reaching an agreement about Iran's right to enrichment, transparency, more inspections of nuclear facilities and the lifting of sanctions.
The hardline Kayhan daily was less optimistic, however.
It highlighted remarks by Foreign Minister Mohammad Javad Zarif that "America should show its good will in practical measures."
Wendy Sherman, the head of the US delegation to the nuclear talks with Iran, urged the US Congress to delay new sanctions against Iran until there is an outcome at the Geneva talks.
Another round of negotiations is to be held on November 7 and 8.