BAGHDAD: Iran and six world powers have wrapped up talks, still far apart over how to oversee Tehran's atomic program but with resolve to keep dialogue going as an alternative to possible military action.

Envoys said Thursday they will meet again next month in Moscow after negotiations stretched out for extra hours and a sandstorm shut the airport in Iraq's capital. But the two sides agreed on little else during two dramatic days of discussions that underscored the serious challenges of reaching accords between Iran and the West.

''It is clear that we both want to make progress, and that there is some common ground,'' European Union foreign policy chief Catherine Ashton, who is formally leading the talks, told reporters. ''However, significant differences remain.

Nonetheless, we do agree on the need for further discussion to expand that common ground.''

Saeed Jalili, Iran's top nuclear negotiator, offered a lukewarm assessment of what the negotiations achieved, in light of European and American refusal to lift tough sanctions as Tehran had hoped.

''The result of the talks was that we were able to get more familiar with the views of each other,'' Jalili said at a press conference after Ashton left.

The Baghdad discussions began with hopes for progress before each side accused the other of failing to offer meaningful, realistic proposals. More tellingly, they also showed that US diplomats and others are pressing neither for quick deals nor for ultimatums that could derail the sensitive talks.

''We are moving in a step-by-step process,'' a senior American official told reporters in Baghdad's heavily protected Green Zone. ''It's good for them. It's good for us. It's good for the world.''

The U.S. has gradually moved off its demands for an immediate and complete halt to Iran's ability to make nuclear fuel, which the West and allies fear could someday provide the foundations of warhead-grade material. Iran denies it seeks atomic arms.

Israeli leaders, on the other hand, have been highly critical of the talks, claiming it allows Iran to buy time and drive a wedge between Washington and Jerusalem. On Wednesday, Israel's defense minister, Ehud Barak, said even possible moves by Iran to open its nuclear facilities to greater UN inspect don't rule out a possible Israeli military strike.