Updated 2:50 p.m. ET
(AP) BAGHDAD - Tough negotiations between Iran and world powers over Tehran's nuclear program ended Thursday with a plan to meet next month for another round of talks but agreement on little else.
The open channels between Iran and the six-nation bloc - the five permanent Security Council members plus Germany - are seen as the most hopeful chances of outreach between Washington and Tehran in years. They also could push back threats of military action that have shaken oil markets and brought worries of triggering a wider Middle East conflict.
European Union foreign policy chief Catherine Ashton said both sides agreed to continue the discussions on June 18-19 in Moscow in hopes of a breakthrough on international concerns about the Islamic Republic's ability to build atomic weapons.
The announcement capped two days of negotiations in Baghdad, where at times it appeared Tehran would withdraw from the talks in frustration over the West's refusal so far to scale back tough economic sanctions.
"It is clear that we both want to make progress, and that there is some common ground," Ashton, who is formally leading the talks, told reporters at the end of the talks. "However, significant differences remain. Nonetheless, we do agree on the need for further discussion to expand that common ground."
Israeli leaders have been 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 U.N. inspection doesn't rule out a possible Israeli military strike.
Iran went into the Baghdad talks seeking guarantees the West will scale back on its sanctions, which have targeted Iran's critical oil exports and have effectively blackballed the country from international banking networks.
Instead, Tehran's negotiators on Thursday rejected proposals by the world powers to curb its nuclear program without getting much in return, calling them unbalanced. Saeed Jalili, Iran's top nuclear negotiator, demanded an overhaul to the Western plan and conveyed his concerns in a private meeting with Ashton on Thursday.
At the heart of the issue are two different proposals. On one side is an incentive package by the six-nation group - the United States, Russia, China, Britain, France and Germany - that seeks to halt the most sensitive part of Iran's nuclear fuel production.
Iran, in turn, wants the U.S. and Europe to ease harsh economic sanctions on its oil exports in return for pledges to give wider access to U.N. inspectors and other concessions.
The West and its allies fear Iran's nuclear program could eventually produce atomic weapons. Iran insists its reactors are only for energy and research.
A senior U.S. official predicted the pace of the talks - which began last month in Istanbul - would speed up in upcoming rounds.
"We are urgent about it, because every day we don't figure this out is a day they keep going forward with a nuclear program," said the U.S. official who spoke on condition of anonymity to discuss the negotiations more candidly. "We still think we have some time for diplomacy, but it's not indefinite."
Hassan Abedini, an executive for Iran's state-run TV channel who was briefed on the discussions, called the proposal put forward by the U.S. and its allies unbalanced and filled only with old plans that Tehran dismissed years ago.
The Western package calls on Tehran to halt the production of 20 percent enriched uranium, which is the highest grade publicly announced by Iran and used for the country's lone medical research reactor. Western leaders fear the material - far above the 3.5 percent enrichment needed for energy-producing reactors - can be turned into warhead grade in a matter of months.
In exchange, the world powers offered benefits, including medical isotopes, some nuclear safety cooperation and spare parts for civilian airliners that are needed in Iran.
But they snubbed Iranian calls for an immediate easing of significant economic sanctions imposed on Tehran for flouting U.N. Security Council resolutions that demand the suspension of all enrichment.
"Giving up 20 percent enrichment levels in return for plane spare parts is a joke," said Abedini. "The package is unbalanced and therefore unacceptable."