Ruben Sprich / Reuters
Iranian Foreign Minister Mohammad Javad Zarif addresses a news conference following nuclear negotiations with European Union's foreign policy chief at the United Nations in Geneva on Wednesday.
Two days of nuclear talks between Iran and six world powers were "substantive and forward-looking," and a second series is set for next month, both sides said in a statement Wednesday.
A representative of the European Union did not go into details about what progress was achieved, but said Iran's foreign minister, Javad Zarif, presented "an outline of the plan" that would be a starting point for future talks.
The White House followed up with its assessment that an Iranian proposal on the table suggests an unprecedented "level of seriousness and substance."
"We found the Iranian presentation very useful," press secretary Jay Carney said.
The discussions are aimed at ending the standoff over Iran's uranium enrichment program — which Tehran says is for peaceful purposes, while other countries fear it could be used to create nuclear weapons.
The election of new, moderate-leaning Iranian President Hassan Rouhani this summer has given the West hope that it can secure concessions about the level and scale of uranium enrichment that could lead to the lifting of crippling economic sanctions.
Despite the promising talks in Geneva this week between Iran, the U.S., Russia, China, Britain, France and Germany, caution prevails.
British Foreign Minister William Hague said in a statement that Iran must make the first move.
"I hope that negotiations will lead soon to concrete results,'' Hague said in a statement. "Iran will need to take the necessary first steps on its program and we are ready to take proportionate steps in return.''
Nuclear negotiations have been deadlocked for a decade, but this latest round comes on the heels of the first direct contact between the U.S. and Iran since 1979: a phone call President Barack Obama placed to Rouhani as he left the United Nations General Assembly last month.
NBC News' Jamieson Lesko, Reuters and the Associated Press contributed to this report.
First published October 16 2013, 11:40 AM