Iranian Foreign Minister Mohammad Javad Zarif said on Monday Tehran would try to "go as far as we can" in negotiations with U.S. Secretary of State John Kerry about Iran's disputed nuclear program.
Zarif, asked if he was confident about the talks scheduled with Kerry in the Swiss town of Montreux on Tuesday, told Reuters Television in Geneva: "We will try. We will try to go as far as we can."
"We are moving forward, we have made some progress since last time and if there is the political will to accept that an agreement and sanctions cannot go together, then we can have an agreement this time," Zarif said, as he prepared for a round of talks with U.S. Secretary of State John Kerry on Tuesday.
Zarif and Kerry, who addressed the UN Human Rights Council in Geneva on Monday, were heading later to Montreux for their talks, to be followed later this week by talks there between political directors from the major powers and Iran.
Meanwhile, head of the United Nations' nuclear watchdog said on Monday Iran had still not handed over key information to his staff, and his body's investigation into Tehran's atomic programme could not continue indefinitely.
"Iran has yet to provide explanations that enable the agency to clarify two outstanding practical measures," chief Yukiya Amano told the body's Board of Governors in Vienna, echoing a report seen by Reuters last month.
The two measures relating to alleged explosives tests and other measures that might have been used for bomb research should have been addressed by Iran by last August.
"The Agency is not in a position to provide credible assurance about the absence of undeclared nuclear material and activities in Iran, and therefore to conclude that all nuclear material in Iran is in peaceful activities," Amano said.
The West fears Iran wants to develop an atomic bomb. Tehran says its nuclear programme is entirely peaceful.
The Agency remains ready to accelerate the resolution of all outstanding issues, he added, but "this process cannot continue indefinitely".
The United States and five other powers are seeking to negotiate an agreement with Iran to curb its nuclear program in exchange for relief from economic sanctions.
They have set a March deadline for a framework deal and a June deadline for a final one.
The IAEA is likely to monitor any possible deal between Iran and the six powers in addition to its own investigation into Iran's nuclear program. Amano said he proposed a 1.8-percent increase to the body's 344-million-euro ($386 million) budget given increased demand for its services.
Amano added that he remained seriously concerned about the nuclear activities of North Korea which quit the nuclear Non-Proliferation Treaty in 1993. The IAEA has not had inspectors on the ground there since they were expelled by North Korea in 2009.