(CNN) -- A new round of nuclear talks between Iran and six other nations begins in Turkey this week, but the U.S. State Department said Thursday it expects no "big breakthroughs" from the session.
The meeting is the second time in just over six weeks that diplomats from the five permanent members of the U.N. Security Council and Germany will sit down with their Iranian counterparts, following a 14-month gap between sessions.
State Department spokesman Mark Toner told reporters Thursday that Washington is looking for the start of "a real process" that leads to progress rather than an immediate breakthrough in Friday's session in Istanbul.
"These are small, incremental steps," Toner said. "We're not expecting any big breakthroughs, but we want to see a constructive process emerge that leads to Iran ... engaging with the international community in a credible
process and engaging and addressing the international community's concerns about its nuclear program."
Iran is under U.N. sanctions for its refusal to halt its production of enriched uranium.
In comments carried by the state news agency Ria Novosti, Russian Foreign Minister Sergei Lavrov suggested Thursday that prospects to drop some of those sanctions could be on the agenda for Friday's talks. But Toner said the U.N. resolutions that established those sanctions are "quite clear" about what Iran has to do to get out from under them.
"We think they've had an effect," he said.
Enriched uranium at low concentrations can be used to fuel power plants, and in extremely high concentrations it can be used to produce a nuclear bomb. The Islamic republic insists that it is within its rights to produce fuel for civilian power plants, but the International Atomic Energy Agency says it can't fully confirm the peaceful nature of the Iranian program.