Iranian nuclear negotiators are scheduled to meet Tuesday in Kazakhstan with officials from the United States, Britain, France, Russia, China, and Germany. The six are pushing for "concrete action" from Iran to comply with international inspections of its nuclear program.
U.S. officials say Iran's installation of more advanced uranium-enrichment centrifuges before these talks is yet another "provocative step."
But State Department spokeswoman Victoria Nuland says Tehran can still take the "diplomatic path" at talks in Kazakhstan.
"The question is whether the Iranian delegation will come to Almaty really ready to roll up their sleeves and help the international community be reassured with regard to their nuclear program," Nuland said.
Iran says it is entitled to a peaceful civilian nuclear program. But the international community says Tehran has not done enough to prove that it is not trying to develop nuclear weapons.
Members of the so-called P5+1 - France, Germany, Britain, China, Russia, and the United States - are working to expand international pressure on Iran to comply with U.N. nuclear inspections. French President Francois Holland in New Delhi:
"India's influence is very important here," noted Hollande, "because it can help to convince the leaders of Iran to enter a serious negotiation, and to bring Iran to respect the international agreements of non-nuclear proliferation."
Johns Hopkins University Professor Ruth Wedgwood questions the effectiveness of U.N. sanctions, even though they have cut the value of Iran's currency and its oil exports.
"But the other lesson of sanctions is: the army eats first," Wedgwood said. "The nuclear program eats first. Countries will give up issues they are not particularly serious about, but they will not give up their core ambitions."
Russian Foreign Minister Sergei Lavrov says the international community must convince Iran that its actions are meant to stop the spread of nuclear weapons, not to bring down the government.
"Iran must know that the overall game plan, if you wish, must see what is in for them in this process. Otherwise, we have to convince Iran that it is not about the regime change," Lavrov said.
Making progress with Iran is especially important following North Korea's nuclear tests.
"They are linked, you connect the dots," said U.S. Secretary of State John Kerry. "It is important for the world to have credibility in respect to our nonproliferation efforts, and just as it is impermissible for North Korea to pursue this kind of reckless effort, so we have said it is impermissible with respect to Iran."
Israeli Prime Minister Benjamin Netanyahu says the failure to stop North Korea shows sanctions will not stop Iran.
"Have sanctions, tough sanctions stopped North Korea? No. And the fact that they produced a nuclear explosion reverberates everywhere in the Middle East, and especially in Iran," noted Netanyahu. "They say 'Where is the world? Where is the international community? Where is the tough response?'"
Israel continues to threaten a military response to prevent Iran from developing nuclear weapons, as the Obama administration works to convince Israeli leaders there is still time for a diplomatic solution.