Iran and the six world powers on Tuesday thrashed out an agreement that limits Tehran's nuclear programme in exchange for lifting over a decade-long economic sanctions.
The comprehensive agreement was clinched between Iran and Britain, China, France, Germany, Russia and the US after over two weeks of difficult negotiations in the Austrian capital.
The text of the deal, which runs into around 100 pages, specifies key areas of the Iranian nuclear issue, including sanction relief and action plan, nuclear technology cooperation, the committee of the monitoring of the implementation, and capping of Iran's nuclear capacity and draft of UN Security Council resolution, Xinhua reported.
Iranian Foreign Minister Mohammad Javad Zarif described the deal as "a historic moment", but acknowledged it was "not perfect".
"I believe this is a historic moment. We are reaching an agreement that is not perfect for anybody but it is what we could accomplish and it is an important achievement for all of us," Zarif said at the final ministerial meeting between Iran and six world powers here.
Iranian President Hassan Rouhani confirmed the deal on Twitter, saying it "shows constructive engagement works".
Yukiya Amano, director general of the International Atomic Energy Agency (IAEA), said he has signed a roadmap with Iran to clarify past and present outstanding issues, according to media reports.
"I have just signed the roadmap between Iran and the IAEA for the clarification of past and present outstanding issues regarding Iran's nuclear programme," he was quoted as saying.
Future access to Iran's Parchin military site, which was repeatedly sought, was part of a separate "arrangement", Amano added.
After Rouhani took office in 2013, Tehran and the six countries intensified the nuclear talks and signed a deal in Geneva in November 2013, under which Tehran would suspend some disputed nuclear activities in exchange for limited sanction relief from Western states, buying time for diplomatic efforts.
In the past 18 months, marathon negotiations between Iran and P5+1 have resolved many tough issues which were once seen as impossible.
Iran for long has said that its nuclear programme was for peaceful purposes. The West feared it could be used to build an atomic bomb.
The movement toward a deal has been marked with years of tough negotiations. The deal is meant to impose long-term, verifiable limits on nuclear programmes that Tehran could modify to produce weapons. Iran, in return, would get tens of billions of dollars in sanctions relief.