At the talks, Iran sits across the table from the P5+1 group, the five permanent members of the UN Security Council - Britain, China, France, Russia and the United States - plus Germany.
In their second meeting in Geneva in less than a month, P5+1 negotiators are talking to Iran for two days in the hopes of working out an agreement on the country's nuclear program.
With Iran seeking relief from economic sanctions, negotiators will push the country to accept constraints.
"I believe it is even possible to reach that agreement this week," Iranian Foreign Minister Javad Zarif told France 24 on Tuesday. "But I can only talk for our side, I cannot talk for the other side."
When he took office in August, Iranian President Hassan Rouhani pledged to engage world powers to resolve the dispute and get sanctions lifted. At last month's talks in Geneva, held in English for the first time, Iran reportedly outlined a two-stage process to resolve the dispute within a year. In return for any concessions, Iran wants the to see the lifting of economic sanctions that have cut daily oil revenues by 60 percent in the past two years and devalued its currency, the rial, by more than half.
"The nuclear talks are complex and have entered a serious phase," said Michael Mann, spokesman for EU foreign policy chief Catherine Ashton, who oversees the talks with Iran on behalf of the powers. "We have to make concrete progress."
For years, the P5+1 group has attempted to negotiate with Iran on its uranium enrichment, which many nations believe in the service of developing nuclear weapons.
Iran has repeatedly denied this, with officials insisting that the country would use its nuclear program only to generate electricity and for medical purposes. The country has, however, enriched uranium to 20 percent purity - only a few technical steps short of producing weapons-grade material.
"I'd be very worried of any partial deals that enable Iran to maintain those capabilities but begin to reduce sanctions ... " Israeli Prime Minister Benjamin Netanyahu has said. "This could undermine the longevity and durability of the sanctions regime."
In skepticism, Netanyahu may have found some common ground with Iran's supreme leader, Ayatollah Ali Khamenei, who has called himself "not optimistic" about the talks, even if experts say his clear endorsement of the negotiators shows that his country takes the talks seriously.
"No one should see our negotiating team as compromisers," Khamenei said on Sunday, adding that they needed Iran's support in their "difficult mission."
mkg/rg (Reuters, AFP)