US Secretary of State Hillary Clinton on Wednesday said it was now "urgent" for Iran to ease concerns over its nuclear program.
Her remarks came at the start of talks among foreign ministers of the G8 – Canada, France, Germany, Italy, Japan, Russia, the United Kingdom, and the United States. The European Union is represented within the G8, but cannot host or chair summits.
Clinton said the upcoming talks between Iran and the P5+1 was "an opportunity for Iran to address seriously the international community's concerns”.
"We believe there is still time for diplomacy, but it is urgent that the Iranians come to the table to establish an environment conducive to achieving concrete results through a sustained process," Clinton said.
Iran is expected to meet representatives of the P5+1 – the five permanent members of the UN Security Council plus Germany – starting on April 14 in Istanbul.
The talks come as Israel and the United States ramp up pressure on Iran over its nuclear program and tensions over a possible strike in Tehran's nuclear facilities run high.
Israeli and Western officials charge Iran is seeking nuclear weapons, but the Islamic Republic claims its nuclear program is for peaceful civilian purposes.
In early March, the head of the IAEA also said there were indications that Iran was engaged in the development of nuclear weapons, an accusation supported in a report submitted by the agency last November.
"Iran is not telling us everything. That is my impression. We are asking Iran to engage with us proactively, and Iran has a case to answer," said IAEA director Yukiya Amano.
His remarks followed two recent IAEA reports that indicated Iran had sought – and likely continues to seek – nuclear technologies of a military nature.
IAEA experts previously reported Iran's production of 20% enriched uranium is far greater than needed for peaceful purposes. They also note Iran's medical research sector is not sufficiently advanced to justify such production.
Key advisor to Supreme Leader Ayatollah Ali Khamenei, Mohammad Javad Larijani, said last month that the West should accept Iran's "peaceful nuclear program," sell Iran 20 percent enriched uranium, and provide the customary assistance nuclear nations provide to those building nuclear power plants.
In return for cooperation from the West Iran would offer "full transparency," Larijani said.
He did not say Iran would halt uranium enrichment – a key demand by Jerusalem and Washington to avoid military strikes – but observers say the stipulation that the West provide 20% enriched uranium indicates Iran is open to doing so.
Iranian chief nuclear negotiator Saeed Jalili said Wednesday he would propose ‘new initiatives’ in the upcoming round of talks.